Add built-in kvp vars to the config manifest in generic

[Greelan]

This is not for requesting support for new games/applications

To do this you should go to https://github.com/CubeCoders/AMPTemplates and first attempt to build a configuration yourself - otherwise you can request a template from this repo.

Feature Request

Feature Information:

The config manifest in generic is unaware of kvp built-in vars like $ExternalIP, $FullBaseDir etc. This means those vars can't be used in things like enum values or default values, at least where they are being used to write out to config files (if they are being used to write to the command line, it is OK, because of course the kvp is aware of them). This should be rectified.

I confirm:

• [x] that I have searched for an existing feature request matching the description.