implement CLI password recovery (hacky :omg:)

+ rewrite migrations logic
+ rename encode_password to hash_password
+ update image sizes (add medium size)
+ rename image endpoints

app/periodic_scan.py

@@ -13,6 +13,12 @@ from app.logger import log
 def run_periodic_scans():
     """
     Runs periodic scans.
+
+    Periodic scans are checks that run every few minutes
+    in the background to do stuff like:
+    - checking for new music
+    - delete deleted entries
+    - downloading artist images, and other data.
     """
     # ValidateAlbumThumbs()
     # ValidatePlaylistThumbs()