Views: if exists / if not exists for DDL (#10831)

[jepett0]

Ticket:

• KIKIMR-22087
• views: IF EXISTS / IF NOT EXISTS to help with scripting view dropping / creation #10818

Backport:

• Views: if exists / if not exists for DDL #10831

[github-actions]

⚪ 2024-10-30 07:22:58 UTC Pre-commit check for 8f39ce3 has started.
⚪ 2024-10-30 07:25:37 UTC Build linux-x86_64-relwithdebinfo is running...
🟢 2024-10-30 08:08:08 UTC Build successful.
⚪ 2024-10-30 08:08:22 UTC Tests are running...
🔴 2024-10-30 10:16:44 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
73442	59955	0	13	13432	42

🟡 2024-10-30 10:17:41 UTC ydbd size 8.2 GiB changed* by +106.5 KiB, which is >= 100.0 KiB vs stable-24-3: Warning

ydbd size dash	stable-24-3: 8ae4726	merge: 8f39ce3	diff	diff %
ydbd size	8 855 911 992 Bytes	8 856 021 088 Bytes	+106.5 KiB	+0.001%
ydbd stripped size	483 568 680 Bytes	483 582 152 Bytes	+13.2 KiB	+0.003%

^{*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]

⚪ 2024-10-30 07:23:00 UTC Pre-commit check for 8f39ce3 has started.
⚪ 2024-10-30 07:25:43 UTC Build linux-x86_64-release-clang14 is running...
🟢 2024-10-30 07:34:20 UTC Build successful.

[github-actions]

⚪ 2024-10-30 07:23:03 UTC Pre-commit check for 8f39ce3 has started.
⚪ 2024-10-30 07:25:46 UTC Build linux-x86_64-release-asan is running...
🟢 2024-10-30 07:52:27 UTC Build successful.
⚪ 2024-10-30 07:52:44 UTC Tests are running...
🔴 2024-10-30 10:04:54 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
12357	12230	0	28	52	47

🟢 2024-10-30 10:05:58 UTC ydbd size 5.6 GiB changed* by +45.9 KiB, which is < 100.0 KiB vs stable-24-3: OK

ydbd size dash	stable-24-3: 8ae4726	merge: 8f39ce3	diff	diff %
ydbd size	5 989 661 248 Bytes	5 989 708 288 Bytes	+45.9 KiB	+0.001%
ydbd stripped size	1 501 284 000 Bytes	1 501 307 616 Bytes	+23.1 KiB	+0.002%

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