appcenter 8.4.0 Released

Other Improvements:

• Updated translations
• Performance improvements

What's Changed

• (Re)introduce a backend interface by @leolost2605 in #2406
• Readme: Remove mention of restart required message by @leolost2605 in #2410
• Remove unused AsyncMutex and SuspendControl by @leolost2605 in #2409
• HumbleButton: Remove unused allow free by @leolost2605 in #2408
• Fix some warnings regarding icons by @leolost2605 in #2412
• Fix empty toast on unknown operation (i.e. currently only update) by @leolost2605 in #2415
• Don't check whether installed view is null because it always is by @leolost2605 in #2418
• Screenshot: Guard against null color by @leolost2605 in #2417
• Fix back button warning by @leolost2605 in #2416
• AppListUpdateView: Clamp to 800 by @leolost2605 in #2407
• AppListUpdateView: set last checked as installed secondary text by @danirabbit in #2420
• Homepage: Drop Appcenter banner by @leolost2605 in #2411
• ChangeInfo: Update properties on the main thread, use property bindings by @leolost2605 in #2405
• Prepare speed up by @leolost2605 in #2419
• Banner: use Granite.HeaderLabel by @danirabbit in #2423
• Banner: simplify construction by @danirabbit in #2422
• Use HeaderLabel size property by @danirabbit in #2425
• AppListUpdateView: Add a queue of working packages by @leolost2605 in #2424
• AppListUpdateView: put size in updates header secondary text by @danirabbit in #2426
• AppStream.Pool: Don't load OS catalog by @leolost2605 in #2428
• ListModels: Use n items instead of custom properties by @leolost2605 in #2427
• ReleasesDialog: Make listbox no select by @leolost2605 in #2429
• Speed up get_packages_for_component_id and prepare for future improvements by @leolost2605 in #2421

Full Changelog: 8.3.2...8.4.0