Feature: Thumbnail Cache Refactoring and Avatar Fixes

This commit acts as a squash of the thumbnail cache refactoring and avatar fixes.

See PR description for full details.

Author: zerox80

opencloudApp/src/main/java/eu/opencloud/android/MainApp.kt

@@ -40,7 +40,7 @@ import androidx.appcompat.app.AlertDialog
 import androidx.core.content.pm.PackageInfoCompat
 import eu.opencloud.android.data.providers.implementation.OCSharedPreferencesProvider
 
-import eu.opencloud.android.datamodel.ThumbnailsCacheManager
+
 import eu.opencloud.android.db.PreferenceManager
 import eu.opencloud.android.dependecyinjection.commonModule
 import eu.opencloud.android.dependecyinjection.localDataSourceModule
@@ -117,8 +117,7 @@ class MainApp : Application() {
 
         SingleSessionManager.setUserAgent(userAgent)
 
-        // initialise thumbnails cache on background thread
-        ThumbnailsCacheManager.InitDiskCacheTask().execute()
+
 
         initDependencyInjection()