(fix)mobile: Improve the gallery to improve scale, double tap, and swipe gesture detection (#1502)

* photoviewgallery

* stiffer scrolling to react more like google photos

* adds a dx threshhold for the swipe/up down from the original dropped point

* stopped wrapping imageview in gallery viewer to avoid the double photoview issue. breaks imageview page pinch-to-zoom, so i need to fix that for other callers

* refactors gallery view to use remoteimage directly and breaks imageviewpage

* removed image_viewer_page

* adds minscale

* adds photo_view to repository

* double tap to zoom out with hacked commit

* double tapping!

* got up and down swipe gestures working

* fixed wrong cache and headers in image providers

* fixed image quality and added videos back in

* local loading asset image fix

* precaches images

* fixes lint errors

* deleted remote_photo_view and more linters

* fixes scale

* load preview and load original

* precache does original / preview as well

* refactored image providers to nice functions and added JPEG thumbnail format to remote image thumbnail lookup

* moved photo_view to shared/ui/

* three stage loading with webp and fixes some thumbnail fits

* fixed local thumbnail

* fixed paging in iOS

mobile/pubspec.yaml

@@ -23,7 +23,6 @@ dependencies:
   video_player: ^2.2.18
   chewie: ^1.3.5
   badges: ^2.0.2
-  photo_view: ^0.14.0
   socket_io_client: ^2.0.0-beta.4-nullsafety.0
   flutter_map: ^0.14.0
   flutter_udid: ^2.0.0
@@ -41,6 +40,7 @@ dependencies:
   collection: ^1.16.0
   http_parser: ^4.0.1
   flutter_web_auth: ^0.5.0
+  easy_image_viewer: ^1.2.0
 
   openapi:
     path: openapi