Update commands and sync the manual install guides

[Trevor McCasland]

In the following file,
https://github.com/openstack/trove/blob/master/doc/source/dev/manual_install.rst

There are references to the keystone client and the old v2 authentication.

We should update these to work with the master branch of code.

There is also duplication of the install guide in the following directory https://github.com/openstack/trove/tree/master/install-guide/source

This was a result of the docs team moving all the install_guides in tree.

Given the former link publishes to docs.openstack.org/developer/trove we should keep this information up to date.