[Streams] [WIP] Rewrite (#782)

* [Streams] [WIP] Rewrite

* [Streams] [WIP] Settings related commands

* [Streams] Moved to Config

* [Streams] Added [p]streamalert stop

* [Streams] Added toggleable autodeletion

* [Streams] Added [p]streamalert list

* [Streams] beam.pro -> Mixer

* V3 streams modifications (#847)

* [Streams] implement mention command

* [Streams] implement mentions in stream alert check

* [Streams] move to 3 separate commands for alert mentions

* [Streams] implement support for alerting for twitch community streams… (#849)

* [Streams] implement support for alerting for twitch community streams (Twentysix26/Red-DiscordBot/issues/824)

* [Streams] async getter implementation

* [Streams] repr for TwitchCommunity class

* [Streams] move and fix imports (#994)

* [Streams] function rename due to duplicate names

* [Streams] drop force_registration

* [Streams] fix command not displaying help

redbot/cogs/streams/errors.py

@@ -0,0 +1,26 @@
+class StreamsError(Exception):
+    pass
+
+
+class StreamNotFound(StreamsError):
+    pass
+
+
+class CommunityNotFound(StreamsError):
+    pass
+
+
+class APIError(StreamsError):
+    pass
+
+
+class InvalidCredentials(StreamsError):
+    pass
+
+
+class OfflineStream(StreamsError):
+    pass
+
+
+class OfflineCommunity(StreamsError):
+    pass