[S58] O1.2: Update infrastructure to automatically rebase tor-browser.git patches onto Firefox-beta so they can be used in nightly builds.

• Implement tooling, (e.g. quilt, gbp-pq) that similar projects (e.g., Tails) use to automate these kinds of code rebase tasks.
• Work with Mozilla to identify any infrastructure we can set up together to help us to automate our rebase process.
• Configure alerts to notify the Tor Browser team when automatic rebasing of patches fails.
• Experiment with and adjust cycle length for automatic rebasing procedures (e.g daily versus weekly versus fortnightly) depending on fallout results of this process.
• Manually fix fallout from automatic rebase process.

• Rebase and squash mobile and desktop patches
• Implement auto-rebasing tooling
• Deploy notifications for auto-rebasing failures