Integrate Statsviz

[codenoid]

Description

Implement Statsviz to debug server as requested in #3529

Closes #3529.

Readiness checklist

• I added/updated unit tests (and they pass).
• I added/updated integration/compatibility tests (and they pass).
• I added/updated comments and checked rendering.
• I made spot refactorings.
• I updated user documentation.
• I ran task all, and it passed.
• I ensured that PR title is good enough for the changelog.
• (for maintainers only) I set Reviewers (@FerretDB/core), Milestone (Next), Labels, Project and project's Sprint fields.
• I marked all done items in this checklist.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #3591 (ad3c176) into main (6131bf4) will decrease coverage by 0.14%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3591      +/-   ##
==========================================
- Coverage   61.65%   61.51%   -0.14%     
==========================================
  Files         426      426              
  Lines       27395    27401       +6     
==========================================
- Hits        16890    16857      -33     
- Misses       9506     9541      +35     
- Partials      999     1003       +4     

Files	Coverage Δ
internal/util/debug/debug.go	87.50% <100.00%> (+1.29%)	⬆️

... and 12 files with indirect coverage changes

Flag	Coverage Δ
filter-true	58.06% <100.00%> (-0.10%)	⬇️
hana-1	?
integration	58.06% <100.00%> (-0.10%)	⬇️
mongodb-1	4.50% <100.00%> (+0.02%)	⬆️
postgresql-1	41.17% <100.00%> (-0.04%)	⬇️
postgresql-2	41.79% <100.00%> (+<0.01%)	⬆️
postgresql-3	40.05% <100.00%> (+0.02%)	⬆️
sort-false	58.06% <100.00%> (-0.10%)	⬇️
sqlite-1	41.07% <100.00%> (+0.04%)	⬆️
sqlite-2	41.96% <100.00%> (+0.02%)	⬆️
sqlite-3	40.07% <100.00%> (-0.02%)	⬇️
unit	22.41% <0.00%> (-0.06%)	⬇️

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[AlekSi]

Thank you!