Cleanups, missing doc items and new test_url capability

This provides a number of cleanups as the code has been unloved for a while.

I've added the ssl-* parameters the robinbowes added in his last patch to the
docs, and found some other cleanups as well where applicable.

I've added the ability to override the test_url also, so that in the future
if a user wishes to they can customize this.

Signed-off-by: Ken Barber <ken@bob.sh>
this section was removed, since we already do validation in puppetdb::server ...