Add GH Community Guidelines

- [ ] `CONTRIBUTING.md`
- These are a little specific to each repo, but at minimum should have build & test directions.
- [ ] [`pull_request_template.md`](https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/creating-a-pull-request-template-for-your-repository)
- Can just use ones I've already made a few times
- [ ] [Issue forms/templates](https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository)
- Forms are a new thing! Should make use of the ones I've already made in a few places and remember to use `envinfo` for Node projects!
- [ ] `CODE_OF_CONDUCT.md`
- I've meant to write up a custom/specific one that takes inspiration from the Contributor Covenant but is more specific in defining actions to help prevent abusers from gaslighting others about their actions

Some of these I should also extract into a `.github` repo as the default for my libraries that don't have one