Fixes #6987 - set unlimited_content_hosts

creation of host-collections with the --max-content-hosts flag also
sets the unlimited_content_host flag.
Fixes #7030 - validates AK max_content_hosts

validates that integer is being passed for max_content_host in
ActivationKey command
Merge pull request #219 from dustint-rh/validate_ak_max_content_hosts

Fixes #7030 - validates AK max_content_hosts
Merge pull request #217 from dustint-rh/hc_set_unlimited

Fixes #6987 - set unlimited_content_hosts