chuni: added SUN support, matchmaking, fixed bugs, added docs

- Added CHUNITHM SUN support
- Added first matchmaking support with CPU spawning and messages
- Fixed wrong `next_idx` calculations
- Added `startDate` to events to spawn the correct items
- Fixed login bonus per version
- Added information to docs

example_config/chuni.yaml

@@ -15,6 +15,9 @@ version:
   12:
     rom: 2.05.00
     data: 2.05.00
+  13:
+    rom: 2.10.00
+    data: 2.10.00
 
 crypto:
   encrypted_only: False