Bug 1837575 - Move Tabbed Browser related files to browser/components/tabbrowser/. r=mconley,desktop-theme-reviewers,zeid,tabbrowser-reviewers,frontend-codestyle-reviewers,Itiel

This is a start, there are more modules and scripts we can/should move, as well as tests.

Differential Revision: https://phabricator.services.mozilla.com/D210676