Add master yaml to spin up student stack upon class creation

1. change snapshot to public and store image with backups which is named CCTC-pfsense. original pfsense image has issues with disk and chkdisk fixes them.
2. Master.yml should be added to the pillar to create a stack for each student (https://git.cybbh.space/CCTC/public/raw/master/heat/CCTC_Master.yaml) to minimize issues when class starts as well as urgency when stack creation fails and class already started. We can test with tempest first, then a small test class.
3. Quotas for instructors should also be added to the pillar.

Changes will probably be needed in: https://git.cybbh.space/vta/saltstack/blob/master/system/common/files/create-classes.sh https://git.cybbh.space/vta/saltstack/blob/master/pillar/common/classes.sls