prevent running migrations if is_fresh_install

+ fix: sqlite3.ProgrammingError: Cannot operate on a closed cursor on ProcessAlbumColors()
+ move processing artist images from periodic_scans to Populate
+ bump hash string limit from 7 to 10
+ add last_mod property to database
+ fix: TypeError: '<' not supported between instances of 'int' and 'str' on album page

app/db/sqlite/queries.py

@@ -37,12 +37,13 @@ CREATE TABLE IF NOT EXISTS tracks (
     artist text NOT NULL,
     bitrate integer NOT NULL,
     copyright text,
-    date text NOT NULL,
+    date integer NOT NULL,
     disc integer NOT NULL,
     duration integer NOT NULL,
     filepath text NOT NULL,
     folder text NOT NULL,
     genre text,
+    last_mod float NOT NULL,
     title text NOT NULL,
     track integer NOT NULL,
     trackhash text NOT NULL,