Having 2 entrypoint seems redudant and complicated for end users,
so instead of rally-manage db <commands> let's use rally db <commands>
This reduces amount of code and commands needed to know to work with
Rally which is actually good.
This patch doesn't remove rally-manage just deprecates it
Change-Id: Ib35db2d22174cd3d3eee0d87358ad07a91dce0d9
* plugin_reference is extended to build data for particular Plugin Base cls
* plugin_reference is extended to build data for all Plugin Bases (instead
of just building data for hardcoded classes).
* cli_reference is extended to build data for particular command
* new include_vars extension is introduced for including const data in docs
Change-Id: I76d9f85e41c6ab8e622f6d3581478962144525ba
