add roles supporting debci

This MR is incomplete. The roles are fairly rudimentary at this point and I'll partially use this description as TODO list for now:

• The default --ram-size for qemu is insufficient and there is no way in debci to change that. #1037245 MR
• munin integration missing, depends on adding plugins to package
• Multihost deployment.
• Use debci packages from unstable (once our MRs are merged)
• Use autopkgtest packages from unstable, depends on not using unsupported ext4 features and
• lvm backend broken for derivatives due to enabling dbgsym
• https
• fix race condition in autopkgtest's find_free_port
• figure out why rabbitmqctl list_queues fails (required for munin)