prom_export: lint, docs updates, other chore/meta

[tigattack]

Initial Checklist

• [ ] Has @tigattack / @issy been added as a reviewer?
• [x] If applicable, have the relevant project(s), milestone(s), and label(s) been applied?
• [ ] If applicable, have you added details of the cog to the readme as per README.md?

Details

Does this resolve an issue?

Several undocumented :eyes:

Changes

• Lint
• Update command docs & docstrings
• Add cog install message
• Add @rippleFCL to contributors
• Add cog requirements to info.json
• Add @tigattack to cog authors
• Rename cog (prom_export -> prometheus_exporter)

Breaking Changes

• Base command changed (prom_exporter -> prom_export)

[rippleFCL]

Could i maby jump in on this? Theres quite a few changes i want to make to this cog if thats ok

[BeryJu]

Also the CI is failing because the markov cog is using dict[str, ...] which isn't supported in python 3.8, it was added in python 3.9

[tigattack]

Could i maby jump in on this? Theres quite a few changes i want to make to this cog if thats ok

@rippleFCL You want me to delay the merge, or you want to add to this branch? If the latter, it'd be best to work on your own branch and create a PR when you're ready.

[rippleFCL]

@tigattack had a dense moment. Yh send the merg lad