Add sphinx docs

[hstock]

• Fixes [feature-request] Sphinx documentation / manpages #101, Refactor parser creation out of parse_ots_args #102
• Added basic sphinx config
• Added basic autogenerated manpage
• Added basic overview page

[petertodd]

Awesome! Let me know when you think this is ready for merging.

[hstock]

Might take a bit, since I discovered a bug in sphinx-argparse which I wanted to use to auto-generate the manpage. It currently bails out when aliases are used with subcommands.

So I guess this should only be merged after they have included the fix.

The whole thing has been prompted by me trying to get the opentimestamps-client into debian (which requires a man page 😉)

For debian I can do with a copy of a locally generated manpage until the fix is also in Debian.

[petertodd]

Ha! Always fun when you find a bug in your tools. :) Good luck, and yeah, I'm happy to wait.