Add 'Issues' and PR templates

[KartavyaSharma]

Pull requests are very much the wild-west right now, at least until I release v1.0 of trapp. Have a PR template that contains type of change (fix, refactor, feat), and for now (for the lack of any new ideas) have a short description of the change. The Issue templates can be multiple and can depend on the type of issue being submitted, is it a bug, config, feature request, etc.

For an example of good issue template variety and examples, check out microsoft/TypeScript https://github.com/microsoft/TypeScript/tree/main/.github/ISSUE_TEMPLATE