feat: use DocsFilter

[forshev]

Description

Use DocsFilter struct in search and fetch

Fixes #290

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[cheb0]

@seqbenchbot up main search-keyword-exact-match-warm

[seqbenchbot]

Oh-oh, @cheb0 ('>o.o)'>!

Something went wrong and I couldn't process your request.
Please take a closer look at error message:

cannot run several comparison benchmarks concurrently

[cheb0]

So, we always wrap a tree into nAnd node with (most of time) empty tombestone iterator. I decided to check if there is a noticeable perf overhead.

For relatively dense histogram (service:X and level:Y) fired against 3 stg fracs It went from 44-46 ms to 46-50 ms (hot case). I used testDocsFilter from fraction_test

[cheb0]

nit (naming): doesn't look like a guy can filter docs. Since, it's able to get tombestone iterator and delete tombstones for a provided frac, It looks like a tombstone storage/provider to me.

[cheb0]

nit: technically it's possible to test deletion in this test. We could just modify testDocsFilter by allowing it to have deleted lids preconfigured and then add this filter as a field of FractionTestSuite. In a test it's possible to just preconfigure some lids deleted (let's say first 3), then bulk insert and if some docs are missing. Maybe I'll add it later.

[cheb0]

@seqbenchbot up main search-keyword-exact-match-warm

[seqbenchbot]

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Identificator for your ongoing benchmark - 76b796bf.

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[cheb0]

@seqbenchbot down 76b796bf

[seqbenchbot]

Nice, @cheb0 <(-^,^-)=b!

The benchmark with identificator 76b796bf was finished.
I've prepared a summary for you. Click on Show summary button to see it:

Show summary

Query	Type	mean (ms)			stddev (ms)			p(50) (ms)			p(95) (ms)			p(99) (ms)			iterations
		base	comp	diff	base	comp	diff	base	comp	diff	base	comp	diff	base	comp	diff	base	comp	diff
bulk	warm	67.31	68.69	+2.05%	23.91	26.49	+10.79%	61.00	61.00	0.00%	116.50	124.00	+6.44%	151.50	157.50	+3.96%	2450.00	2450.00	0.00%
service:payment-backend-eu AND k8s_namespace:prod	warm	120.96	122.50	+1.28%	112.08	111.98	-0.09%	99.00	105.00	+6.06%	232.00	234.00	+0.86%	758.50	748.50	-1.32%	7652.00	7407.00	-3.20%

Have a great time!