control: Setup configured zone groups retrieval

Configured zone groups come from either a compile time YAML generated
`_zoneLayouts` list or from a future list created at runtime after
parsing a set of JSON configuration files.

Tested:
    No impact to YAML driven configurations
    Empty list of zone groups created when use of JSON enabled

Change-Id: I3253ccf5c54e5397d5de0b7105fc3918dc59e24a
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
3 files changed