Share assets from mobile to other apps (#435)

* Share unique assets

* Style share preparing dialog

* Share assets from multiselect

* Fix i18n

* Use navigator like in delete dialog

* Center bottom-bar buttons

mobile/lib/modules/asset_viewer/ui/top_control_app_bar.dart

@@ -11,12 +11,14 @@ class TopControlAppBar extends ConsumerWidget with PreferredSizeWidget {
     required this.asset,
     required this.onMoreInfoPressed,
     required this.onDownloadPressed,
+    required this.onSharePressed,
     this.loading = false
   }) : super(key: key);
 
   final AssetResponseDto asset;
   final Function onMoreInfoPressed;
   final Function onDownloadPressed;
+  final Function onSharePressed;
   final bool loading;
 
   @override
@@ -63,6 +65,14 @@ class TopControlAppBar extends ConsumerWidget with PreferredSizeWidget {
               ? const Icon(Icons.favorite_rounded)
               : const Icon(Icons.favorite_border_rounded),
         ),
+        IconButton(
+          iconSize: iconSize,
+          splashRadius: iconSize,
+          onPressed: () {
+            onSharePressed();
+          },
+          icon: const Icon(Icons.share),
+        ),
         IconButton(
           iconSize: iconSize,
           splashRadius: iconSize,