Add IsSystem flag to filestore config; support __filestore_space_limit_ssd_system limit in SchemeShard

[SvartMetal]

Changelog entry

We are going to use newly introduced IsSystem flag for filestore shards in order to have separate accounting for them.
Shards should be considered as system entities and should not be accounted as regular 'user-created' filestores.

...

• New feature

Additional information

This feature is implemented by analogy with existing __volume_space_limit_ssd_system
...

[github-actions]

⚪ 2024-12-17 23:17:50 UTC Pre-commit check linux-x86_64-release-asan for 5cc16b1 has started.
⚪ 2024-12-17 23:18:02 UTC Artifacts will be uploaded here
⚪ 2024-12-17 23:21:17 UTC ya make is running...
🟡 2024-12-18 01:04:26 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
14020	13917	0	50	6	47

🟢 2024-12-18 01:05:35 UTC Build successful.
🟢 2024-12-18 01:06:03 UTC ydbd size 3.6 GiB changed* by +12.3 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: dffc12a	merge: 5cc16b1	diff	diff %
ydbd size	3 894 689 168 Bytes	3 894 701 808 Bytes	+12.3 KiB	+0.000%
ydbd stripped size	1 363 873 328 Bytes	1 363 879 024 Bytes	+5.6 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]

⚪ 2024-12-17 23:17:59 UTC Pre-commit check linux-x86_64-relwithdebinfo for 5cc16b1 has started.
⚪ 2024-12-17 23:18:10 UTC Artifacts will be uploaded here
⚪ 2024-12-17 23:21:25 UTC ya make is running...
🟡 2024-12-18 00:47:37 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?
31019	28074	0	1	2830	114

⚪ 2024-12-18 00:50:10 UTC ya make is running... (failed tests rerun, try 2)
🟢 2024-12-18 01:04:11 UTC Tests successful.

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

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
159 (only retried tests)	50	0	0	0	109

🟢 2024-12-18 01:04:18 UTC Build successful.
🟢 2024-12-18 01:04:37 UTC ydbd size 2.1 GiB changed* by +3.8 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: dffc12a	merge: 5cc16b1	diff	diff %
ydbd size	2 253 799 152 Bytes	2 253 803 088 Bytes	+3.8 KiB	+0.000%
ydbd stripped size	483 054 512 Bytes	483 055 664 Bytes	+1.1 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}