Separate config params for client and server

[artlowel]

Now we have the GlobalConfig object in place, it might still be a good idea to inject some variables in it via webpack's DefinePlugin.

e.g. if the REST API is running on the same server, it is more efficient to use localhost in the REST API baseURL. But on the client it will only work if you use the server's hostname. Extracting that as a variable and injecting it at build time would allow us to end up with a different GlobalConfiguration object on client and server