Update provisio and presto-maven-plugins

They were picking up the wrong version of the takari-lifecycle-plugin.
Use absolute references for document links
Add initial connector documentation

Starting documentation for built-in connectors: sys, jmx and tpch.

This is essential information for new Presto users, but it is currently
only available in a smattering of posts on the Presto Google group. This
adds some basic information into the documentation. Each section needs to
be developed, but this is a good starting point.
Change equals() for Signature
Add a hashChannel column for hash partitioned pages
Add benchmark for HashPagePartitionFunction
Remove redundant override annotation