* Add a middleware for browser refresh.
* Introduce a middleware that can connect to the dotnet-watch change server
* dotnet-watch: Inject the middleware in 3.1 or apps using start hooks \ hosting startup
https://github.com/dotnet/aspnetcore/issues/23412
* Update src/Tools/dotnet-watch/BrowserRefresh/src/StartupHook.cs
* Changes per PR comments
* Add a test for reading the script
* Changes per PR comments
* Updates docs
* Fixup test
* Add project ref
Pranav K