DHCP Server denyunknown is missing "Allow all clients" value

[FallenHighlander]

Is your feature request related to a problem? Please describe.
The GUI has option "Allow all clients" to be selected, but it cannot be selected when using ansible

Describe the solution you'd like
Add another value among "enabled" and "class", for example "all", that would set the correct "Allow all clients parameter"

Describe alternatives you've considered
I can currently change the parameters from the GUI after ansible has ran, but it's not nice to do always.

Additional context

[opoplawski]

So, simply not specifying denyunknown should be the equivalent of selecting "Allow all clients". However, this is not at all obvious. I'll see if that can be made more explicit. There also needs to be a way to change it from one of the other settings to that one.