feat: introduce Markdown linter and formatter

[opeco17]

What this PR does / why we need it:

This PR introduces markdownlint-cli2, the linter and formatter for Markdown files.
make lint will be able to check the format of Markdown files and make lint-fix fix them.

Since some rules can't be fixed by markdownlint-cli2 automatically, I've disabled those rules temporarily.
They should be enabled one by one once it's fixed.

How does this change affect the cardinality of KSM: (increases, decreases or does not change cardinality)
does not change cardinality

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #2178

[mrueg]

Thanks, this is looking good! Two things from my side:

• I would want to understand when a list is - and when it's okay to use *. Do you know which criteria the linter has?
• Can you add it as a github action job ci-markdown-lint?

[opeco17]

Hi, @mrueg
Thank you for the comment

I would want to understand when a list is - and when it's okay to use *. Do you know which criteria the linter has?

According to this document, it's possible to use * by setting a parameter in jsonc .
I've updated that setting and formatted Markdown files.

Can you add it as a github action job ci-markdown-lint?

Linter to Markdown is called in make lint command.
So it can run in CI without updating ci.yaml

lint: shellcheck licensecheck lint-markdown-format
	golangci-lint run

[dgrisonnet]

/triage accepted
/assign @mrueg @dgrisonnet

[mrueg]

Thanks, a small couple of nits in the Makefile. Other than that looks good to me.

[opeco17]

@mrueg

Thank you for your suggestions!
I've merged all of them

[mrueg]

/lgtm

Thanks for your contribution!

[k8s-ci-robot]

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