Media inserter: Add pagination, and consolidate component with pattern inserter and global styles revisions - #77176

What?

Part of:

• Dynamic galleries and media attached to a post #76955

Add pagination to the media inserter in the inserter sidebar.

Why?

As described in the linked issue, media insertion in the sidebar is pretty basic at the moment and it only shows the latest results. I think we can make this area a little more usable, with pagination for example.

At the same time, I noticed we had a different implementation for pagination in the pattern inserter and in the global styles revisions UI. Since we're adding a third place where pagination needs to occur, this PR also proposes consolidating them into the one thing.

How?

• Create a shared Pagination component in the block editor that can be used in a few different places
• Add it to the pattern inserter, use it in the global styles revisions panel, but most importantly for this PR:
• Add it to the media inserter sidebar area

To-do

• Make sure we can get the total number of items and pages (this might require some plumbing)
• Make a call on whether this pagination should be sticky or not (my instinct is "yes", however it also needs to look good, which it doesn't quite... yet)

Testing Instructions

TBC but basically we'll be testing:

• That the global styles revisions pagination works as on trunk and isn't too different
• That the pagination for Patterns still works and (hopefully) looks a bit more consistent / polished
• That the pagination for Media works and looks okay

Screenshots or screencast

Patterns pagination (before)

Patterns pagination (after)

Media pagination

Note this uses a slightly different UI because in code we don't (yet) know how many items or pages are available. That's a "to-do"