[Reminder] Add reminder

This is a fork of ZeLarpMaster's cog with extra commands to list reminders, forget specific reminders, and basic timezone offset consideration as his repo is unmaintained/archived.

reminder/__init__.py

@@ -0,0 +1,12 @@
+from .reminder import Reminder
+
+__red_end_user_data_statement__ = (
+    "This cog stores data provided by users for the express purpose of redisplaying. "
+    "It does not store user data which was not provided through a command. "
+    "Users may remove their own content without making a data removal request. "
+    "This cog does not support data requests, but will respect deletion requests."
+)
+
+
+async def setup(bot):
+    bot.add_cog(Reminder(bot))