Indication for package list update is too shallow

If I let a 0.96 client update its package list / sources, it will do it, but in the background, only visible by an item on the top bar. There is no actual view which gives one feedback "yes, user, you tapped that button, now something happens". In the optimal case, it should display a progress intent (or however its called in this case) like before, and only if you exit it should switch to a background task. Also, the icon should already point out that it is an F-Droid update, the current icon which is only an arrow is too generic.

If we add pull to update (swipe down to update) with a "working" UI at the top of the app list, that UI could be also used for manually requested updates.

CC @eighthave

mentioned in issue #397 (closed)

Added ui update labels

mentioned in issue #538

mentioned in issue #505 (closed)

Milestone changed to 1.0

Assigning to 1.0 since its duplicate was assigned to it.

mentioned in issue #659 (closed)

mentioned in issue #341 (closed)

mentioned in merge request !290 (closed)

FYI a basic version of this is implemented in !463 (merged):

initial-update-feedback

This could be enhanced in the future to show more detailed feedback.