chore: add async search limits metrics

[forshev]

Description

Add async search disk usage limit and concurrency limit metrics.
This allows to use these values as alerts' thresholds

Moved async search metrics to a separate file

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.60%. Comparing base (fd2ede2) to head (1cff88b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #310      +/-   ##
==========================================
+ Coverage   71.57%   71.60%   +0.02%     
==========================================
  Files         204      204              
  Lines       14735    14737       +2     
==========================================
+ Hits        10547    10552       +5     
+ Misses       3432     3431       -1     
+ Partials      756      754       -2     

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[github-actions]

🔴 Performance Degradation

Some benchmarks have degraded compared to the previous run.
Click on Show table button to see full list of degraded benchmarks.

Show table

Name	Previous	Current	Ratio	Verdict
FindSequence_Random/large-4	fd2ede	c5ae32
	13510.24 MB/s	12075.94 MB/s	0.89	🔴
	1213.00 ns/op	1357.00 ns/op	1.12	🔴
FindSequence_Random/small-4	fd2ede	c5ae32
	5273.54 MB/s	3738.69 MB/s	0.71	🔴
	48.54 ns/op	68.47 ns/op	1.41	🔴