Branch protection rules and general settings

[johannes-lindgren]

I would prefer to use rulesets rather than branch protection rules. (They do mostly the same thing)

Ruleset:

1. Require 0 approvers, or require 1 while allowing maintainer to override.
2. Require code integration tests to pass
3. Require title check to pass
4. Require pull request (no commits directly to main)

In general settings:

• Allow only squash and merge. This will ensure a linear version history.
• Automatically delete the branch after the pull request is merged. (It can be restored via GitHub if needed)
• (optional) When clicking squash and merge, copy the PR description to the commit message
• Enable this button