Dynamic app start / stop PoC

Usage

To build and start:

dotnet build
dotnet run

It will start listening on localhost:5000

Use following routes (all GETs) to start / stop applications:

/start/1
/stop/1
/start/2
/stop/2

Apps register respectively /App1/ and /App2/ routes.
Both apps also register /main, but it's ignored, because they can only handle requests starting with the app's name
Both apps use WordWritingHandler, but they use different implementation of IWordProvider
Apps register absolute routes, but it would be trivial to support only relative routes. That is, app's registration of /main, but would result in registration of <app-name>/main
This example doesn't use MVC, because using MVC requires a lot of dependencies to be set up. In Starcounter we probably wouldn't want vanilla MVC anyway.