Begin work on a data request API (#4045)

[Core] Data Deletion And Disclosure APIs

 - Adds a Data Deletion API
   - Deletion comes in a few forms based on who is requesting
   - Deletion must be handled by 3rd party
 - Adds a Data Collection Disclosure Command
   - Provides a dynamically generated statement from 3rd party
   extensions
 - Modifies the always available commands to be cog compatible
   - Also prevents them from being unloaded accidentally

docs/framework_commands.rst

@@ -13,6 +13,14 @@ extend functionalities used throughout the bot, as outlined below.
 
 .. autofunction:: redbot.core.commands.group
 
+.. autoclass:: redbot.core.commands.Cog
+
+    .. automethod:: format_help_for_context
+    
+    .. automethod:: red_get_data_for_user
+    
+    .. automethod:: red_delete_data_for_user
+
 .. autoclass:: redbot.core.commands.Command
     :members:
     :inherited-members: format_help_for_context