[Admin] Code prettification and bugfixing (#3250)

* Facelift for Admin

* Remove unnecessary converter, reorder existing steps

* Delete admin.py

* Delete __init__.py

* Delete test_admin.py

* Remove one extra unneeded check

* Create 3250.bugfix.1.rst

* Create 3250.bugfix.2.rst

* Create 3250.bugfix.3.rst

* Create 3250.bugfix.4.rst

* Create 3250.misc.1.rst

* Create 3250.misc.2.rst

* Create 3250.misc.3.rst

* Create 3250.breaking.1.rst

* Create 3250.breaking.2.rst

* ...

* I hate black...

redbot/cogs/admin/converters.py

@@ -5,31 +5,18 @@ from redbot.core.i18n import Translator
 _ = Translator("AdminConverters", __file__)
 
 
-class MemberDefaultAuthor(commands.Converter):
-    async def convert(self, ctx: commands.Context, arg: str) -> discord.Member:
-        member_converter = commands.MemberConverter()
-        try:
-            member = await member_converter.convert(ctx, arg)
-        except commands.BadArgument:
-            if arg.strip() != "":
-                raise
-            else:
-                member = ctx.author
-        return member
-
-
 class SelfRole(commands.Converter):
     async def convert(self, ctx: commands.Context, arg: str) -> discord.Role:
         admin = ctx.command.cog
         if admin is None:
             raise commands.BadArgument(_("The Admin cog is not loaded."))
 
-        conf = admin.conf
-        selfroles = await conf.guild(ctx.guild).selfroles()
-
         role_converter = commands.RoleConverter()
         role = await role_converter.convert(ctx, arg)
 
+        conf = admin.conf
+        selfroles = await conf.guild(ctx.guild).selfroles()
+
         if role.id not in selfroles:
             raise commands.BadArgument(_("The provided role is not a valid selfrole."))
         return role