feature (sponsors): Add sponsor command.

Add new sponsor prompts.
Add new sponsor command.
Add `sponsor_text` table.
Add sponsor global config settings.
Update `Setting.command` to use new `widget`.
Add custom `cmd_str` support to `Message` `SettingType`.

bot/modules/sponsors/__init__.py

@@ -0,0 +1,5 @@
+from . import module
+
+from . import data
+from . import config
+from . import commands