Add typescript support

1. I've replaced lodash with lodash-es, so it can be tree-shaken
2. ~/init is a directory with application modules that run before app is mounted. Useful for configuration, web socket connection, and other stuff. Basically, everything here runs on the Loading Funkwhale... screen.
3. ~/composables is a directory with our custom composables. Much like ~/utils but each util is in its own file
4. I've removed sending selected theme to the backend as discussed with @georgkrause (only from frontend)

Fixes #1215 (closed), #1297 (closed), #1298 (closed), #1326 (closed), #1363 (closed), #1377 (closed), #1379 (closed), #1381 (closed), #1471 (closed), #1536 (closed), #1547 (closed), #1567 (closed), #1581 (closed), #1634 (closed), #1635 (closed), #1636 (closed), #1647 (closed), #1759 (closed), #1721 (closed), #1761 (closed), #1762 (closed), #1766 (closed), #1777 (closed), #1796 (closed), #1802 (closed), #1828 (closed), #1829 (closed), #1836 (closed), #1844 (closed), #1845 (closed)