Mnt make sphinx

[jklymak]

This makes the landing page a sphinx document. I think I got all the elements from the existing landing page.

The advantage here is that it can use mpl-sphinx-theme and will maintain a consistent navbar and style with the main site. It also builds like a normal sphinx site, and the body and headers are kept more separate. Note that it is just implemented all in docs/body.html

We should decide if we are going to do this or not before too many changes are made to the rest of the brochure site because this will be a bit of a pain to rebase.

[lgtm-com[bot]]

This pull request fixes 5 alerts when merging 2ef3c135314132352f8382309757f92a9c1cf25f into ac00c6829903995bda3428d7f06cf2a4ccb76f54 - view on LGTM.com

fixed alerts:

• 2 for Useless conditional
• 1 for Variable not declared before use
• 1 for Missing variable declaration
• 1 for Unused variable, import, function or class