Introduce keystone:config

This keystone::config is aim to use keystone_config resources
to manage custom configurations in keystone config files.

This will make end user easy to add their own custom options
in Hiera data.

Fully implements blueprint keystone-custom-config

Change-Id: I1e0742382bfca3f627029c7f17fe05fd9d3d0dbe
Add ability to configure any catalog driver

Add a catalog_driver parameter which can be used to bypass
the catalog_type parameter and offer finer control over
the catalog driver configuration in Keystone.

Closes-bug: #1301592
Change-Id: If062c855c875cf06e192593181898ba0a185a91a
Merge "Add ability to configure any catalog driver"