modularize src

+ merge main.py and manage.py
+ move start logic to swingmusic/__main__.py
+ add a run.py on the project root

swingmusic/utils/unicode.py

@@ -0,0 +1,5 @@
+def handle_unicode(string: str):
+    """
+    Handles Unicode errors by ignoring unicode characters
+    """
+    return string.encode("utf-16", "ignore").decode("utf-16")