Is your feature request related to a problem? Please describe.

At the moment, users aren't made aware of the way extensions work. In an addition (or as part of an overhaul) help should give a description of what koala extensions are

Requirements

1. Add an explanation to the top of k!help to describe how to use extensions (k!enable, list and disable Ext)
2. Create a framework for 'k!tutorial ' command that will give the user a description of how to use the given extension (or left blank for base features)
3. Create a tutorial k!tutorial for the base features (adding extensions, changing the welcome message etc.)

Describe alternatives you've considered

A copy paste of this tutorial for each extension could be used in the frontend.

Additional context

N/A