[chore] add githubgen to enhance codeowners and issue templates

[mowies]

This PR

• adds the githubgen tool as a dependency in internal/tools
• uses githubgen to generate codeowners and issue template files
• updates lots of metadata files by
  • taking the existing codeowners file and feeding the info from there back into the component metadata.yaml files or creating new metadata.yaml files where none existed yet
• adds distributions.yaml as a basis the mostly already existing distributions: keys in metadata.yaml files (needed for githubgen to work correctly)
• adds relevant make commands to make the githubgen tool usage mostly transparent to users

This change is a prerequisite to be able to ping codeowners reliably with automated tooling as a next step.

Part of #11562

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.41%. Comparing base (7d603aa) to head (7897671).
Report is 1 commits behind head on main.

Additional details and impacted files

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##             main   #11756   +/-   ##
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  Coverage   91.41%   91.41%           
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  Files         467      467           
  Lines       25583    25583           
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  Hits        23387    23387           
  Misses       1778     1778           
  Partials      418      418           

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[evan-bradley]

Follow ups: move the githubgen tool to a central place so that we don't need to duplicate it in contrib and core repos

https://github.com/open-telemetry/opentelemetry-go-build-tools/ is probably the right place. Could we just pull the module from contrib (like we do with chloggen) and if we move it update the reference? Referencing it in the internal/tools package should be fairly straightforward.

[mowies]

@evan-bradley that would be possible but I made a few minor changes to the tool to make it work with this repo (e.g. changing the file templates), so that would need to be parameterized in the original tool first to be able to do that. I wanted to do exactly that in a follow up issue afterwards to be able to clearly see what we need to change in the tool to make it general enough to serve both or even more repos in the future.

[mowies]

I filed open-telemetry/opentelemetry-collector-contrib#36691 to take care of moving githubgen to the build-tools repo

[atoulme]

yes, go-build-tools seems like a better home.

[mx-psi]

@mowies Do you think moving to go-build-tools as a first step is doable? I think it's probably less of a hassle than copying the code here

[mowies]

I'm already working on it :)
Draft PR is open, but that will take a little bit cus the tool has 0 unit tests

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[mowies]

this is still active

[andrzej-stencel]

This should be connector/xconnector, right?

Suggested change

	- connector/x
	- connector/xconnector

[mowies]

this is kind of a limitation of the githubgen tool currently. I didn't get around to fix it yet, but I think for now it should be fine. I don't think those components are selected often if at all in the issue templates.

[mx-psi]

I will merge this in one week if there are no further comments cc @open-telemetry/collector-approvers