[virtual] Parameterize scenarios based on PDF/IDF

[virtual] Parameterize scenarios based on PDF/IDF

NOTE: only os-nosdn-nofeature-noha is parameterized for now.

- move config drive & disk creation from prepare_vms to create_vms;
- make default disk size(s) configurable based on scenario defaults
  and vPDF;
  * compute nodes require 2 disks to be defined in vPDF, since the
    pillar reclass model assumes /dev/vdb is reserved for cinder;
  * if multiple disks are defined in vPDF, they are created and
    attached accordinly (only ctl01 and cmp nodes are parameterized
    in this change; only for the os-nosdn-nofeature-noha scenario);
- vCPU specifications are deduced based on vPDF (sockets, cores);
  * threads/core is hard set to 2 since vPDF does not have a key
    for it;
  * NUMA resources are distributed evenly based on the number of
    sockets configured in PDF;
  * no less than the mininum requirement for a scenario is allocated
    (e.g. if PDF specifies 2 cores, but the scenario requires at
    least 4 cores, the larger value will be used);
- RAM is deduced based on PDF (but no less than the mininum req is
  allocated, e.g. if PDF specifies 2GB RAM for computes, but the
  scenario requires at least 8GB, the larger value will be used);

Change-Id: I97188aa2a1006865b8429eb6483e10c76795f7d2
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>