Change `dev` Guidance To Rebase

[TimothyWillard]

Currently we use both rebases and merge commits for pulling PRs into dev which can create a headache for updating PRs using either method. We should stick to a single method for pulling PRs into dev and main.

1. Need to add a note to the development documentation that we prefer "rebase and merge" over "create a merge commit".
2. Also should investigate branch rules for enforcing said preference, I know it is possible and have done it before but need to decide on the set of rules that we would like.