initial MVP- Palo Alto Firewall Module

[kpdhulipala]

initial MVP- Palo Alto Firewall Module - Onboarding terraform module to create network edge Palo Alto Firewall Device with three device management types (INTERNET -ACCESS, PRIVATE and INTERNET-ACCESS-WITH-PRVT-MGMT)

1. Single device
2. HA device
3. Cluster device

[ctreatma]

I had one non-blocking comment about the docs; otherwise this looks good to me in terms of module structure and syntax.

[displague]

I didn't see #9. I defer to #8 (comment) which came in a couple of minutes before my comments. The module structure looks good.