Ability to remove_extra_config_element()

[atistler]

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

I cannot remove 'extra config elements' from a VM.

Describe the solution you'd like

There is currently the ability to:

def add_extra_config_element(self, key, value, required=False):

It would be helpful to allow the ability to remove extra config by key as well:

def remove_extra_config_element(self, key):

Describe alternatives you've considered

No response

Additional context

No response