UI polish tasks

[hrydgard]

• [x] Easier way to record frame dumps directly from within the app, so we don't need the wiki page.
  • [ ] Maybe even automatically zip up and e-mail?
• [x] Clickable notifications - useful for the above, and maybe some other things #19020
• [x] Uninstalling homebrew should be on a background thread, just like installing. Currently, uninstalling Suicide Barbie freezes the UI for 20 seconds (!) on phones with scoped storage
• [ ] Reorganize system settings: #16877. Carefully!
• [ ] Add support for DPI setting
  • Would help https://github.com/hrydgard/ppsspp/issues/12644
• [x] Remote games tab #18317
• [x] Async load of savestate screenshots #18538
• [ ] Better descriptions for tex upscaler #17071

[NABN00B]

Related to #16877.

[hrydgard]

Fixed three things, leaving the rest for 1.18.