Add menu button to quickly clear browsing data

[ichthyosaurus]

This adds a menu button to quickly clear browsing data without having to open the settings page first.

Unexpanded menu:

Before:

After:

[pvuorela]

The menu is already a bit crowded with items so there should be big enough need for adding something new. I'm not sure if removing browsing data has such a need. There is the private mode, and for clearing this saves only one tap. Shouldn't be that common need to go clearing the browsing data?

[ichthyosaurus]

I often clear my browsing data because I want to get rid of cookies but I also want to keep the history (that's why I don't use private mode). (Also, there's no official way to always start in private mode but that's a different issue.)

That takes 7 taps and 2 swipes without #1118 and without #1120, or 6 taps and 2 swipes with #1120, or 2 taps and 3 swipes with #1118 and #1120.

[pvuorela]

I guess you are still in minority in your way of clearing cookies. The shortcut you would get is a UI complexity addition for others. Small one but they accumulate over features. Out of the taps and swipes, this particular should be saving only one tap, I think.

Maybe easier savings on the clearing view, defaulting to everything feels indeed excessive. More on that on the other PR.