Support provisioning VMs via boot disk based

[flymia]

Is your feature request related to a problem? Please describe.
As of right now, when trying to create a host using boot disk based deployment, I get an error saying:

is an unsupported provisioning method, available: build,new_volume,new_interface,image

Describe the solution you'd like
I want to use the boot disk based provisioning.

Describe alternatives you've considered
Using other provisioning methods are possible, but not as simple as this one. When using VMware, I can provision the VM all through the Foreman UI and it boots the correct ISO all the way automatically.

Additional context
Maybe use the Proxmox API to upload the host ISO, set it as boot disk and then you are good to go.

The documentation states: https://docs.theforeman.org/nightly/Provisioning_Hosts/index-katello.html#Creating_Hosts_on_Proxmox_proxmox-provisioning

If the foreman_bootdisk plugin is installed and you want to use boot-disk provisioning, click Boot disk based.

But this is simply not possible, since it is greyed out.

[Manisha15]

Proxmox does support bootdisk based host deployment usin foreman_bootdisk.