add button to bookmark queued videos on main player

[hunkjazz]

Describe the feature you want

A button to bookmark queued videos in a playlist, just like background
player has.

Is your feature request related to a problem? Please describe it

The problem is that it's impossible to bookmark queued videos, if not
using the background player.

Additional context

I order to avoid a bloated UI, this button could be placed next to
shuffle and repeat buttons, which are under list icon in main player.

How will you/everyone benefit from this feature?

As opposed to being forced to play queued videos on background (so one
can bookmark these), it would be better (in terms of UX) to allow them
to do it directly in main player.