Lots of stuff out of date in the documentation

[ceriottm]

Chemiscope has evolved a lot over the past year, and the documentation needs to be updated a bit. Things I noticed quickly, probably more to find:

• The about box mentions GPL license for JMol, but we don't use JMol anymore
• Many of the figures in the docs are screenshots of an old interface
• The example of usage of the web components, https://chemiscope.org/docs/embedding.html#usage-example doesn't seem to work (or at least, we should explain how that HTML can be used
• We should check that the schema at https://chemiscope.org/docs/tutorial/input-reference.html is up-do-date.

Bonus: figuring out how to make sure the documentation doesn't get out-of-date again.

[Luthaf]

The about box mentions GPL license for JMol, but we don't use JMol anymore

Will be fixed by #256

The example of usage of the web components, https://chemiscope.org/docs/embedding.html#usage-example doesn't seem to work (or at least, we should explain how that HTML can be used

I'll have a look, but this code is missing the dataset loading part, meaning one can not just copy/paste it around.

[jwa7]

Just to add to this - there should be a section in the README that highlights that chemiscope can be easily installed for use in jupyter notebooks simply by using pip install chemiscope and not going through all the npm build/install process