[WEB] Select album thumbnail (#383)

* Added context menu for album opionts

* choose asset for album thumbnail

* Refactor UpdateAlbumDto to accept albumThumbnailAssetId

* implemented changing album cover on web

* Fixed api change on mobile app

web/src/routes/albums/[albumId]/index.svelte

@@ -45,6 +45,6 @@
 	<title>{album.albumName} - Immich</title>
 </svelte:head>
 
-<div class="relative immich-scrollbar">
+<div class="immich-scrollbar">
 	<AlbumViewer {album} />
 </div>