Add Documentation for blender add-on and code

[Aadjou]

We need documentation for 3d artists

• installation
• features and options
• use from command line

And documentation for the code for contributors

• design and structure of the add-on
• documentation of code

[AVGP]

can we break out the beginner-friendly parts in smaller issues?

Installation / Features / CLI are three wonderfully self-contained parts, code and design may require more coaching to document

[Aadjou]

Yes.

[AVGP]

See #10 and #11