Add HCL generation advice header

[patrickcping]

• Add a header to each generated file that states:

  • The origin (Ping CTL)
  • The date/time of generation (to compare with other generated files)
  • Advice on the import {} block use with linkout to Hashicorp's docs
  • Advice on working through plan errors

• Add a new doc that describes the manual actions that need to be taken to work around terraform plan errors generated by the provider, due to config generation limitations out of our control

[erikostien-pingidentity]

Looks great! I think a small test case expected error changed with the header logic that needs to be addressed.