Define clear contribution guidelines

[euanwm]

Define a clear approach to contributing to this repo.

Top level ideas:

• Squash & merge for PRs
• Branch naming to be fix, chore, feature, and db.
• Tests are not strictly required but nice to have.
• Issues can be raised but templates must be followed.
• Discord channel to be used for discussions.

[Veerhan-glitch]

hey can u assign it to me?