We are adding a notification to tell users they can change their
language. It needs new strings, and I have decided to use Fluent for
them, for a series of reasons.

However, it is the first component to use Fluent, and it needs to be
translated with Weblate, but we are not moving base-browser to Weblate,
yet.
So, we are using another branch on translation.git and we need a new
project to fetch it, which I am adding with this commit.

Also, I have changed how we manage base-browser translations, and
transformed the TT for to a bash for, to keep the Firefox build script
shorter, which is helpful for build debugging sessions.

Changed remaining URLs in GitLab issue templates.

With c52bc0e5, projects/tor-browser was
renamed to project/browser. However we forgot to update that path in a
few files:
- LICENSE
- tools/changelog-format-blog-post
- .gitlab/issue_templates/Release Prep - Alpha.md

This one will need to be updated after 12.0 stable is released:
- .gitlab/issue_templates/Release Prep - Stable.md

Added the instructions to update the new base-browser translation files,
and the instructions to update the manual.

added android rebasing steps and other misc fixes

add android publishing steps

added explicit signing steps

various updates and tweaks, stubs for different android projects

openssl tar.gz URL doesn't need to be manually updated as it is programmitically generated from the version