Adjust to uBlock web extension

We need to update how we generate its database as the format has changed (see https://bugs.debian.org/877040 for details and useful pointers).

Drop bin/convert-ublock-settings if it’s not needed (i.e. if it does not actually save space in .git)
Update release process and bin/convert-ublock-settings if needed.

Feature Branch: feature/15023-tor-browser-8

Original created by @intrigeri on 15702 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information