Minimal ViperConfig for ViperCoreServer

[ArquintL]

Gobra Server has emitted the following error during CI on a Windows machine:

[scallop] Error: Validation failure for 'port' option parameters: 

Gobra Server was configured to use port 50009 but this port configuration is handled by Gobra Server and is not forwarded to ViperCoreServer (we pass an empty array of args to ViperCoreServer).
However, I couldn't find any other component that could cause the above error and I suspect ViperConfig somehow being unable to find a free port (which is the default behavior).
As ViperCoreServer does not seem to use any port (which is also not a task for ViperCoreServer), I request to remove this config option from ViperConfig and maybe move it to a separate config (e.g. ViperHttpConfig).
As part of this change, one could strip ViperConfig down to the minimum set of options that ViperCoreServer needs (and therefore call it ViperCoreServerConfig).