Use circular buffer for zap logs

[fenogentov]

Closes #564.

[codecov]

Codecov Report

Merging #585 (6275b60) into main (d03d6a0) will increase coverage by 0.14%.
The diff coverage is 100.00%.

❗ Current head 6275b60 differs from pull request most recent head 9486c10. Consider uploading reports for the commit 9486c10 to get more accurate results

@@            Coverage Diff             @@
##             main     #585      +/-   ##
==========================================
+ Coverage   63.44%   63.59%   +0.14%     
==========================================
  Files         191      192       +1     
  Lines        7636     7667      +31     
==========================================
+ Hits         4845     4876      +31     
  Misses       2233     2233              
  Partials      558      558              

Impacted Files	Coverage Δ
internal/util/logging/logging.go	71.42% <100.00%> (+11.42%)	⬆️
internal/util/logging/logram.go	100.00% <100.00%> (ø)

Flag	Coverage Δ
FerretDB	59.17% <54.54%> (-0.04%)	⬇️
MongoDB	6.34% <54.54%> (+0.18%)	⬆️
integration	59.20% <54.54%> (-0.04%)	⬇️
unit	23.48% <100.00%> (+0.44%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

[AlekSi]

We should also add a method to get stored entires back as a slice ([]zap.Entry), covering cases when ring buffer is not full yet. I.e. we should not always return 1024 slice elements with some of them being nil

[seeforschauer]

As for me, PR task was also unclear and very interesting. )
I read #420 and #564 and understood a few.
@fenogentov I would be thankful if yod' tell all the benefits of this. (i.e. why does FerretDB need this task? Wait, maybe @AlekSi can explain better, what is the issue is solved? Anyway, what is the thing with it?)

[seeforschauer]

@fenogentov linters failing.

[seeforschauer]

package description is required, unfortunately, I can't find it.
everything else LGTM.

[fenogentov]

package description is required, unfortunately, I can't find it. everything else LGTM.

logging package is common, so the description of the structure explains why this functionality