Add blog post on running FerretDB and CloudNativePG on Kubernetes

[Fashander]

Description

Closes FerretDB/engineering#177

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.

[mergify]

Marketing blog posts should be reviewed by @ptrfarkas and @AlekSi.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.51%. Comparing base (ee7a8b1) to head (17a8902).
Report is 1 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (ee7a8b1) and HEAD (17a8902). Click for more details.

HEAD has 59 uploads less than BASE

| Flag | BASE (ee7a8b1) | HEAD (17a8902) | |------|------|------| |integration|41|16| |filter-true|32|16| |sqlite-4|2|1| |sqlite-2|4|1| |postgresql-2|4|2| |postgresql-3|4|1| |sqlite-3|4|1| |sqlite-1|4|1| |postgresql-1|4|1| |sqlite-5|2|1| |postgresql-5|2|1| |mongodb-1|1|2| |unit|1|2|

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #4377       +/-   ##
===========================================
- Coverage   74.95%   63.51%   -11.44%     
===========================================
  Files         323      323               
  Lines       22398    22398               
===========================================
- Hits        16788    14226     -2562     
- Misses       4399     6887     +2488     
- Partials     1211     1285       +74     

see 102 files with indirect coverage changes

Flag	Coverage Δ
filter-false	?
filter-true	55.05% <ø> (-15.07%)	⬇️
hana-1	0.00% <ø> (-3.39%)	⬇️
integration	55.05% <ø> (-15.11%)	⬇️
mongodb-1	5.05% <ø> (ø)
mysql-1	?
mysql-2	?
mysql-3	?
postgresql-1	21.84% <ø> (-33.19%)	⬇️
postgresql-2	44.96% <ø> (-8.65%)	⬇️
postgresql-3	24.44% <ø> (-28.12%)	⬇️
postgresql-4	40.27% <ø> (-0.01%)	⬇️
postgresql-5	20.21% <ø> (-23.56%)	⬇️
sqlite-1	21.29% <ø> (-32.71%)	⬇️
sqlite-2	22.98% <ø> (-29.69%)	⬇️
sqlite-3	23.84% <ø> (-27.74%)	⬇️
sqlite-4	21.66% <ø> (-17.76%)	⬇️
sqlite-5	19.53% <ø> (-23.49%)	⬇️
unit	33.04% <ø> (ø)

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

[chilagrow]

Please check the namespace consistency across the blog and test commands 🙏

[chilagrow]

@Fashander I think you've renamed something and few commands are not working, could you go over the entire doc and ensure commands work please 🤗

[chilagrow]

See comment

[chilagrow]

Nice post!

[AlekSi]

LGTM, let's bump the date.

[Fashander]

@AlekSi PTAL