[Mod] Add two new settings to disable name/nickname tracking (#4799)

* Add default settings for name tracking

* Add configuration command for name tracking

* Check the track names settings before tracking

* *grumble*

* Fix permissions levels

* Update settings.py

* Use clean_prefix in inline, and don't use f-strings in `_()`

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/cogs/mod/events.py

@@ -161,6 +161,9 @@ class Events(MixinMeta):
     @commands.Cog.listener()
     async def on_user_update(self, before: discord.User, after: discord.User):
         if before.name != after.name:
+            track_all_names = await self.config.track_all_names()
+            if not track_all_names:
+                return
             async with self.config.user(before).past_names() as name_list:
                 while None in name_list:  # clean out null entries from a bug
                     name_list.remove(None)
@@ -177,6 +180,10 @@ class Events(MixinMeta):
             guild = after.guild
             if (not guild) or await self.bot.cog_disabled_in_guild(self, guild):
                 return
+            track_all_names = await self.config.track_all_names()
+            track_nicknames = await self.config.guild(guild).track_nicknames()
+            if (not track_all_names) or (not track_nicknames):
+                return
             async with self.config.member(before).past_nicks() as nick_list:
                 while None in nick_list:  # clean out null entries from a bug
                     nick_list.remove(None)