Restructure documentation

[sruehs]

some small improvements would be nice to have in the docs folder:

• no duplicate notebooks
• favicon to _static folder
• clean-up and add pointers

[VeckoTheGecko]

Also refresh the website (update homepage to reduce friction to getting to the tutorials)

[VeckoTheGecko]

[ ] clean-up and add pointers

@sruehs could you elaborate on this?