[V3 Config] Require custom group initialization before usage (#2545)

* Require custom group initialization before usage and write that data to disk

* Style

* add tests

* remove custom info update method from drivers

* clean up remnant

* Turn config objects into a singleton to deal with custom group identifiers

* Fix dumbassery

* Stupid stupid stupid

redbot/cogs/reports/reports.py

@@ -45,6 +45,7 @@ class Reports(commands.Cog):
         self.bot = bot
         self.config = Config.get_conf(self, 78631113035100160, force_registration=True)
         self.config.register_guild(**self.default_guild_settings)
+        self.config.init_custom("REPORT", 2)
         self.config.register_custom("REPORT", **self.default_report)
         self.antispam = {}
         self.user_cache = []