Cleanup old validation

[rumyantseva]

Description

This PR refs #693.
In this part, we remove all the validation to add it from scratch 🤓
I will send another PR that adds the correct validation back.

Readiness checklist

• I added tests for new functionality or bugfixes.
• I ran task all, and it passed.
• I added/updated comments for both exported and unexported top-level declarations (functions, types, etc).
• I checked comments rendering with task godocs.
• I ensured that the title is good enough for the changelog.
• (for maintainers only) I set Reviewers (@FerretDB/core), Assignee, Labels, Project and project's Sprint fields.
• I marked all done items in this checklist.

[vercel]

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Name	Status	Preview	Updated
ferret-db	✅ Ready (Inspect)	Visit Preview	Oct 12, 2022 at 6:58AM (UTC)

[codecov]

Codecov Report

Merging #1179 (e8a77f1) into main (8ab516d) will decrease coverage by 0.29%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1179      +/-   ##
==========================================
- Coverage   66.58%   66.29%   -0.30%     
==========================================
  Files         268      268              
  Lines       12974    12881      -93     
==========================================
- Hits         8639     8539     -100     
- Misses       3390     3395       +5     
- Partials      945      947       +2     

Impacted Files	Coverage Δ
internal/types/array.go	85.10% <ø> (+1.29%)	⬆️
internal/types/types.go	77.35% <ø> (-8.53%)	⬇️
internal/util/testutil/equal.go	51.59% <ø> (ø)
internal/wire/op_query.go	32.14% <ø> (ø)
internal/types/document.go	87.34% <100.00%> (+2.16%)	⬆️
internal/util/version/version.go	48.52% <0.00%> (-4.42%)	⬇️
internal/bson/document.go	44.02% <0.00%> (-3.08%)	⬇️
internal/wire/op_msg.go	48.35% <0.00%> (-1.41%)	⬇️
internal/handlers/common/filter.go	86.58% <0.00%> (-0.63%)	⬇️

Flag	Coverage Δ
integration	61.06% <100.00%> (+0.02%)	⬆️
mongodb	13.80% <50.00%> (-0.27%)	⬇️
pg	50.83% <100.00%> (-0.02%)	⬇️
tigris	32.98% <50.00%> (-0.10%)	⬇️
unit	25.70% <100.00%> (-0.57%)	⬇️

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[AlekSi]

Integration test still fails

[w84thesun]

LGTM