Allow changing server.properties from GUI

[jojomatik]

Is your feature request related to a problem? Please describe.
Currently it is not possible to modify properties in server.properties. Some properties such as the port are already loaded but cannot be changed.

Describe the solution you'd like
Add a subset of the properties from server.properties to the GUI and make them editable. After a change the user should have the option to save and restart.

Describe alternatives you've considered
None.

Additional context
Properties should probably live a in similar view as described in #355