* initial commits around using any id servers
* add your own id server for admin area
* lots of refactoring, now instead of injecting IWebHostBuilder we just set the Ocelot base url as a configuration extension method..this means people can pass it in on the command line aswell as hardcode which is OK I guess, also can now use your own IdentityServer to authenticate admin area
* updated docs for #231
* some tests that hopefully bump up coverage