Updated Sphinx theme for main docs

[ncoghlan]

The current CPython docs don't match the new theme, and also don't render well on mobile devices. It would be desirable to update the Python 3.4 and dev docs to a new mobile friendly theme.

http://hg.python.org/cpython/file/default/Doc/tools/sphinxext/

[ericholscher]

+1. The Read the Docs theme looks great on mobile, if you need prior art. The alabaster theme also has good mobile styles:

https://github.com/snide/sphinx_rtd_theme
https://github.com/bitprophet/alabaster

[benjaminp]

This should really be on bugs.python.org.

[ncoghlan]

Jesse & Georg asked to have it here, since the intent is to get the pydotorg folks to put it together for us.

[benjaminp]

Oh, I see, you want a Sphinx theme designed to match the new www.python.org site. I thought you wanted to use a different builtin sphinx theme.

[hugovk]

The https://docs.python.org theme has changed a lot over the last 10 years and is now responsive and has a dark them.

@ncoghlan I think this issue can be closed now?

We can use https://github.com/python/python-docs-theme for new issues about the theme, and there's also some discussion in python/docs-community#1.