Update CONTRIBUTING guidelines

Spawned off of https://repo1.dso.mil/groups/platform-one/big-bang/-/epics/62

UPDATE: 09/19/23

• All of the repos should be updated to reflect the new contributing guidelines. Please review/verify all packages and make sure they are all up to date.

This should encompass updating docs (CONTRIBUTING.md for all repos?) to document the process for a community member to contribute to Big Bang. Depending on the implementation of this epic on a whole this might be documenting the Github Fork -> PR workflow, Gitlab Fork -> MR workflow, or something else.