Adds functionality to modify VM resources

Adds functionality to modify VM resources

VM resources (vcpus, memory, disk size) are now configurable in the
opnfv_ksgen_settings files.  Each node in the ksgen settings file now
has "memory, cpus, disk" attributes:
 - cpus is an integer number of CPUs to assign to the VM
 - memory is an integer size in kilobytes
 - disk is an integer size in gigabytes

The vagrant box vmdk is resized for each VM.  Each VM will then modify
its partition to the new size, execute the normal reboot, then extend
the physical+logical volumes and filesystem using vagrant provisioning
scripts.

JIRA: APEX-1

Change-Id: I471319db14d2189052961b2f533c65850ebeb1e7
Signed-off-by: Tim Rozet <trozet@redhat.com>