setup: Fix thinko for test_require

It is test_require who should list all packages needed for testing, but
because of thinko in 3833be7e (Convert db resolvers to storage
resolvers.) it was the other way.

This resulted in zodburi install always pulling in mock. Fix it.

Fixed: changes in 2.2 broke the zconfig resolver.

testing whether RTD will now build with latest ZEO

I hate forking.

Support more db parameters

pool_timeout, cache_size_bytes, historical_pool_size,
historical_cache_size, historical_cache_size_bytes,
historical_timeout, and large_record_size

comment out latex_logo to get RTD to build

Change to using package pylons-sphinx-themes and remove git submodule

Add pylons-sphinx-themes to tox deps. Probably not the best way to do it, per https://github.com/Pylons/pylons-sphinx-themes#update-toxini

- Note that RTD has not been building. For some reason, RTD tries to install an alpha version of ZEO. See https://readthedocs.org/projects/zodburi/builds/4246953/

Add missing ClientStorage constructor kw args to resolver.

Fix link to documentation