Refactor the "loading image" from Multiplayer into a reusable Widget

[SomeTroglodyte]

... Yes I had the urge to reuse it, and it was the trigger to that package reorg

Thing is - can' test it completely. The Widget itself is tested in FasterUIDevelopment and just fine, the in-game one renders, but of course I get no events, so... Testers?

Implementation notes:

• Using the new kotlin time stuff, as I found extensive use of Java Duration and such a challenge must be answered. Still - needs that OptIn annotation, and Studio often is blind to it and complains. Repair IDE twice fixes that...
• Original had Gdx Actions mixed with Coroutines - 'nah', an Action can do delays on the fly. After some XP it boiled down to one really surprisingly simple line.

[yairm210]

If you're going to genericize this, then get rid of references to multiplayer in the loading image

[SomeTroglodyte]

Yup, slightly more parameters, but cleaner

[SomeTroglodyte]

Just so you know where this may be going:

Peek.2023-10-07.newgame.map.loading.mp4

[SomeTroglodyte]

Re-tested, still works.