[frontend] Built-in auto updater (#3845)

Checks latest release and opens a dialog containing the changelog, and
allow the user to select a specific build to download. After
downloading, it prompts the user to open it.

On Windows, this just opens up the zip in File Explorer. In the future setup files will be available. On macOS this opens up the DMG in Finder so the user can drag it to the Applications folder. Android retains the auto-update functionality from before, but updated to the new scheme. Body/View on Forgejo are not implemented, that should be in a future PR.

Additionally, moved some common httplib incantations to `Common::Net`. This will serve as the common network accessor and JSON parser from here on out.

TODO:
- [x] android :(
- [x] Search for builds based on keywords, with weights towards certain builds (e.g. macOS will search for dmg then tar.gz, windows msvc then mingw/exe then zip, etc.)
- [x] remove linux leftovers
- [x] don't allow asset selection on platforms w/o assets
- [x] nightly changelog should be in the real

FUTURE IMPLEMENTATION:
- [ ] Body/View on Forgejo for Android
- [ ] Setup files for Windows (Eden/nightly are separate) -- maybe portable/setup selector?
- [ ] Something else I'm forgetting

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3845

CMakeModules/GenerateSCMRev.cmake

@@ -33,9 +33,11 @@ endif()
 set(GIT_DESC ${BUILD_VERSION})
 
 # Generate cpp with Git revision from template
-# Also if this is a CI build, add the build name (ie: Nightly, Canary) to the scm_rev file as well
 
-# Auto-updater metadata! Must somewhat mirror GitHub/Forgejo API endpoint
+# TODO(crueter): Stable releases feed.
+set(BUILD_AUTO_UPDATE_STABLE_REPO "eden-emu/eden")
+set(BUILD_AUTO_UPDATE_STABLE_API "git.eden-emu.dev")
+set(BUILD_AUTO_UPDATE_STABLE_API_PATH "/api/v1/repos/")
 
 set(BUILD_AUTO_UPDATE_API_PATH "/latest/release.json")
 if (NIGHTLY_BUILD)