Mobile tab grouping

[droidcraft]

With the ability to move tabs currently in nightly it would also be nice to be able to group tabs the same way chrome does.

[Excite]

@Jon I think the extent to which new users are signing up specifically in order to post on this issue reflects a pretty big disconnect between the community and the developers. 

"Exploring potential ways to improve tab management" would be great for 2018, but it's 2023 and there already is a design that improves tab management from the current Firefox implementation. No one is asking for a reinvented wheel here — let's not let perfect be the enemy of good. Good already exists, it's time to get off the pot and implement.