[needs websockets] plugin install progress

[PartyWumpus]

Please tick as appropriate:

• [x] I have tested this code on a steam deck or on a PC
• [ ] My changes generate no new errors/warnings
• [ ] This is a bugfix/hotfix
• [x] This is a new feature

If you're wanting to update a translation or add a new one, please use the weblate page: https://weblate.werwolv.net/projects/decky/

Description

This fixes issue: #595

Adds progress bars to the plugin install modal, and to the mass updater modal. Relies heavily on stuff in websockets though so won't be showing up in mainline decky until that's done.

https://github.com/SteamDeckHomebrew/decky-loader/assets/48649272/c5d47811-2bbd-4cb0-87d4-e17b53145070

https://github.com/SteamDeckHomebrew/decky-loader/assets/48649272/bc54cf18-c4bb-471b-a97a-7574089824e0

[AAGaming00]

might look nicer either in the top right of the popup or inside the install button IMO

or perhaps as a bar going across the top of the modal

[AAGaming00]

also don't use the fa spinner, use the one in DFL

[PartyWumpus]

also don't use the fa spinner, use the one in DFL

I switched to a downloading icon, which makes more sense I think anyways. The point of a spinner (or as the cool kids say: an annular throbber) is to show progress is happening when there's no progress bar, but... there's a progress bar.

might look nicer either in the top right of the popup or inside the install button IMO

or perhaps as a bar going across the top of the modal

Tried a couple other positions and honestly it looks best here. Might look better stretching the whole way across the modal but not sure. Going to merge as-is and it can be improved later by someone who knows what a good ui looks like.

Also I fixed the bug you see in the clip where the progress bar doesn't reset properly at the start of a new download.