Add ameba

[straight-shoota]

Adds configuration and a CI job for https://github.com/crystal-ameba/ameba

I let ameba generate a config (ameba --gen-config) but replaced all exclusions with hard disables. Then I fixed the violations for some of the rules, which have already been merged in the last couple of days. So I removed the disables for these rules.

The configuration is annotated with explanations in code.

I have disabled most Naming and Style rules because most had large numbers of violations and some of them seem questionable. We can consider enabling some of the in the future, piece by piece

For review, it's best to ignore the first three commits and review the rest combined, not the individual commits.
Depends on #15860, #15870

Resolves #14608
Closes #14631

[ysbaddaden]

That's a lot of disabled rules. How many are left 😅

[straight-shoota]

$ ameba -r | tail -n1
Total rules: 77 / 45 enabled
$ ameba -v
1.6.4
$ ameba-master -r | tail -n1
Total rules: 101 / 58 enabled
$ ameba-master -v
1.7.0-dev

[Sija]

This has been already fixed.

Suggested change

	# BUG: https://github.com/crystal-ameba/ameba/issues/612
	Lint/TopLevelOperatorDefinition:
	Enabled: false

[Sija]

ditto

Suggested change

	# BUG: https://github.com/crystal-ameba/ameba/issues/614
	Style/ParenthesesAroundCondition:
	Enabled: false

[straight-shoota]

The fix is only in master. Latest ameba release is still broken.
There are also still other violations of this rule. This is a TODO for a follow-up.

[Sija]

Whole 1.7.0-dev is only in master, so... 🤷‍♂️

[Sija]

That was just fixed and landed in master.

Suggested change

	Lint/LiteralInInterpolation:
	Excluded:
	- spec/std/random_spec.cr # BUG: https://github.com/crystal-ameba/ameba/issues/611

[straight-shoota]

@Sija I'll merge this as is. The purpose of this PR is to setup a basic configuration. It's not meant to be the final word. Further changes just cause more delays, which creates friction.
We can address all disabled rules in follow-ups.