Initial commit for pulp_openstack

This is based heavily on pulp_docker, along with the ISO filetype in pulp
platform.

:birthday: Happy 0th birthday to pulp_openstack!
a quick and dirty script:

```bash
for s in $(awk -F= '{print $1}' common/pulp_openstack/common/constants.py | grep -e '^[A-Z]'); do echo $s; git grep $s | wc -l; done```

Anything >1 is used elsewhere