Add connection factory to a connector

[buhtr]

Description for reviewers

Added three connection factories:

• TSingleConnectionFactory
• TNewOnEachRequestConnectionFactory (default)
• TFixedPoolConnectionFactory
  ...

[github-actions]

⚪ 2025-03-19 09:54:40 UTC Pre-commit check linux-x86_64-release-asan for 2615234 has started.
⚪ 2025-03-19 09:54:55 UTC Artifacts will be uploaded here
⚪ 2025-03-19 09:57:45 UTC ya make is running...
🟡 2025-03-19 11:17:55 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
12221	12082	0	82	23	34

⚪ 2025-03-19 11:19:12 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-03-19 11:31:33 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
194 (only retried tests)	151	0	1	9	33

⚪ 2025-03-19 11:31:45 UTC ya make is running... (failed tests rerun, try 3)
🟡 2025-03-19 11:43:35 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
71 (only retried tests)	35	0	1	3	32

🟢 2025-03-19 11:43:42 UTC Build successful.
🟢 2025-03-19 11:44:11 UTC ydbd size 3.8 GiB changed* by -23.9 KiB, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 54876e5	merge: 2615234	diff	diff %
ydbd size	4 050 511 448 Bytes	4 050 487 024 Bytes	-23.9 KiB	-0.001%
ydbd stripped size	1 401 252 168 Bytes	1 401 240 488 Bytes	-11.4 KiB	-0.001%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

🟢 2025-03-19 13:39:26 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-03-19 09:58:18 UTC Pre-commit check linux-x86_64-relwithdebinfo for 2615234 has started.
⚪ 2025-03-19 09:58:24 UTC Artifacts will be uploaded here
⚪ 2025-03-19 10:01:07 UTC ya make is running...
🟡 2025-03-19 11:08:24 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
26647	24040	0	5	2489	113

⚪ 2025-03-19 11:10:44 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-03-19 11:26:09 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
163 (only retried tests)	53	0	0	0	110

🟢 2025-03-19 11:26:22 UTC Build successful.
🟢 2025-03-19 11:26:43 UTC ydbd size 2.1 GiB changed* by -8.7 KiB, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 54876e5	merge: 2615234	diff	diff %
ydbd size	2 300 443 720 Bytes	2 300 434 840 Bytes	-8.7 KiB	-0.000%
ydbd stripped size	481 489 536 Bytes	481 487 552 Bytes	-1.9 KiB	-0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-03-20 08:57:50 UTC Pre-commit check linux-x86_64-release-asan for da1e805 has started.
⚪ 2025-03-20 08:58:05 UTC Artifacts will be uploaded here
⚪ 2025-03-20 09:00:56 UTC ya make is running...

[github-actions]

⚪ 2025-03-20 08:58:29 UTC Pre-commit check linux-x86_64-relwithdebinfo for da1e805 has started.
⚪ 2025-03-20 08:58:44 UTC Artifacts will be uploaded here
⚪ 2025-03-20 09:01:29 UTC ya make is running...
⚫ 2025-03-20 09:15:42 UTC Check cancelled

[github-actions]

⚪ 2025-03-20 09:22:38 UTC Pre-commit check linux-x86_64-release-asan for bf45c4d has started.
⚪ 2025-03-20 09:22:53 UTC Artifacts will be uploaded here
⚪ 2025-03-20 09:25:51 UTC ya make is running...
🟡 2025-03-20 10:35:55 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
12228	12133	0	39	19	37

⚪ 2025-03-20 10:37:01 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-03-20 10:52:53 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
138 (only retried tests)	95	0	3	7	33

⚪ 2025-03-20 10:53:01 UTC ya make is running... (failed tests rerun, try 3)
🟡 2025-03-20 11:10:20 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
68 (only retried tests)	31	0	1	6	30

🟢 2025-03-20 11:10:27 UTC Build successful.
🟢 2025-03-20 11:10:55 UTC ydbd size 3.8 GiB changed* by +31.3 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: e22fad1	merge: bf45c4d	diff	diff %
ydbd size	4 052 806 216 Bytes	4 052 838 224 Bytes	+31.3 KiB	+0.001%
ydbd stripped size	1 401 813 384 Bytes	1 401 816 680 Bytes	+3.2 KiB	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-03-20 09:23:55 UTC Pre-commit check linux-x86_64-relwithdebinfo for bf45c4d has started.
⚪ 2025-03-20 09:24:10 UTC Artifacts will be uploaded here
⚪ 2025-03-20 09:27:01 UTC ya make is running...
🟡 2025-03-20 10:35:27 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
26655	24047	0	3	2492	113

⚪ 2025-03-20 10:37:52 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-03-20 10:49:43 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
167 (only retried tests)	58	0	0	3	106

🟢 2025-03-20 10:49:51 UTC Build successful.
🟢 2025-03-20 10:50:10 UTC ydbd size 2.1 GiB changed* by +30.8 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: e22fad1	merge: bf45c4d	diff	diff %
ydbd size	2 301 856 832 Bytes	2 301 888 384 Bytes	+30.8 KiB	+0.001%
ydbd stripped size	481 672 320 Bytes	481 677 568 Bytes	+5.1 KiB	+0.001%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}