Add a method to enable DHCP Server

[kgawda]

Is your feature request related to a problem? Please describe.

Please add an option to Edge DHCP server. Currently pyvcloud allows to add and manage DHCP Pools entries. However, to make them work one needs to enable DHCP server (visible as "DHCP Service Status" in Edge Services Web UI of Cloud Director). Moreover, this is automatically turned off by Cloud Director when all DHCP Pools are removed (and stays off when new entries are added - see image below). As a result, it is not possible to create a working DHCP-based environment from scratch (i.e. starting from empty environment).

Describe the solution you'd like

Add a new method in Gateway class (pyvcloud/pyvcloud/vcd/gateway.py). E.g.: set_dhcp_status(self, enabled).
This should allow to enable/disable DHCP server.

Describe alternatives you've considered

Current workaround: Enable DHCP Server manually via web gui

Additional context

No response