The bit mask used for the type when compressing variants in the
Multiplayer API became too small to represent all variant types.
This commit expand the mask, which means we no longer have an extra bit
in the "meta" byte we use to store encoding information.
The extra bit was only used in case of booleans to store the value and
since booleans do not require extra encoding information we use those 2
bits to store the value instead.
- RPC configurations are now dictionaries.
- Script.get_rpc_methods renamed to Script.get_rpc_config.
- Node.rpc[_id] and Callable.rpc now return an Error.
- Refactor MultiplayerAPI to allow extension.
- New MultiplayerAPI.rpc method with Array argument (for scripts).
- Move the default MultiplayerAPI implementation to a module.
