Create a specific track for i386 support

It is possible to create a separate track to build the application against older bases, we need to maintain two git branches, though...

Subtasks

[ ] Create the i386 Git branch based on pre-core22-migration
[ ] Cherry-pick applicable changes after the migration on the main branch
[ ] Apply for the creation of the i386 track in the Snapcraft Forum
[ ] Create a project on Launchpad
[ ] Setup snap build from the i386 git branch to the i386 track on Launchpad.
[ ] Migrate users from the latest track to the i386 track