Change allowed_slots param type in bigip_vcmp_guest to match F5 expected type

[jasonjuenger]

The allowedSlots parameter in the F5 API is of type list of int. Currently the bigip_vcmp_guest module has this parameter as a list of str. When the module does a compare against the value from the F5 (list of int) and the variable supplied to the module (list of str) it always reports a diff. This results in Ansible reporting a change to the guest even when the configuration being pushed matches what is on the F5. Changing the parameter type in the module to a list of int to match what F5 expects correctly returns 'OK' when the allowed_slots variable matches what is configured on the F5.

This change was successfully tested on Ansible version 2.15.8 and F5 version 15.1.10.2 Build 0.44.2.

Closes #2394