Add local kmeans actor scan

[MBkkt]

It run kmeans for datashard with embeddings.

This scan contains 3 phases:

1. First iteration collect sample of clusters
2. Then N iterations recompute clusters (main cycle of batched kmeans)
3. Finally last iteration upload clusters to level table and postings to corresponding posting table

Important note, that this code doesn't contains slow-path (that can store some intermediate results to LocalDB).
Because in general slow-path will be run only if this code fails and at the same time, datashards are small enough to don't think about this in first implementation of vector index (another words granularity of work that needed to be re-done in case datashard restart <= datashard size)

[github-actions]

⚪ 2024-09-09 10:44:20 UTC Pre-commit check linux-x86_64-relwithdebinfo for 7a9d92c has started.
⚪ 2024-09-09 10:47:45 UTC ya make is running...
🟡 2024-09-09 12:08:44 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
76454	62617	0	45	13768	24

⚪ 2024-09-09 12:16:44 UTC ya make is running... (failed tests rerun, try 2)
🟡 2024-09-09 12:24:29 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
79 (only retried tests)	56	0	6	0	17

⚪ 2024-09-09 12:24:37 UTC ya make is running... (failed tests rerun, try 3)
🔴 2024-09-09 12:32:40 UTC Some tests failed, follow the links below.

Test history | Ya make output

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
28 (only retried tests)	6	0	5	0	17

🟢 2024-09-09 12:32:46 UTC Build successful.
🔴 2024-09-09 12:33:29 UTC ydbd size 8.4 GiB changed* by +3.7 MiB, which is >= 2.0 MiB vs main: Alert

ydbd size dash	main: b440d31	merge: 7a9d92c	diff	diff %
ydbd size	9 017 352 288 Bytes	9 021 234 472 Bytes	+3.7 MiB	+0.043%
ydbd stripped size	487 429 128 Bytes	487 647 240 Bytes	+213.0 KiB	+0.045%

^{*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]

⚪ 2024-09-09 10:45:14 UTC Pre-commit check linux-x86_64-release-asan for 7a9d92c has started.
⚪ 2024-09-09 10:48:36 UTC ya make is running...
🔴 2024-09-09 12:38:31 UTC Some tests failed, follow the links below.

Test history | Ya make output

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
14144	13966	0	51	95	32

🟢 2024-09-09 12:39:51 UTC Build successful.
🔴 2024-09-09 12:40:27 UTC ydbd size 5.6 GiB changed* by +2.8 MiB, which is >= 2.0 MiB vs main: Alert

ydbd size dash	main: b440d31	merge: 7a9d92c	diff	diff %
ydbd size	6 032 161 600 Bytes	6 035 051 528 Bytes	+2.8 MiB	+0.048%
ydbd stripped size	1 510 169 648 Bytes	1 510 821 552 Bytes	+636.6 KiB	+0.043%

^{*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]

⚪ 2024-09-09 10:45:17 UTC Pre-commit check linux-x86_64-release-clang14 for 7a9d92c has started.
⚪ 2024-09-09 10:48:35 UTC ya make is running...
🟢 2024-09-09 11:02:16 UTC Build successful.