Extend LUIS:build to add intent/entities information #1234

Is your feature request related to a problem? Please describe.
In order to support the SDK priming work we need to be able to know the LUIS intents/entities that can be recognized from a particular model and we need to generate that information during building. This is the PR for the SDK: microsoft/botbuilder-dotnet#5477

Describe the solution you'd like
When luis:build is run add the 'recognizes' property with the names of all of the intents and entities that are defined in the LU file like this:

{
    "luis": {
        "sand7_en_us_lu": {
            "appId": "618a3f00-a1a3-4ea5-a228-9bc54ce6204c",
            "recognizes": ["intent1", "intent2", "entity1", ...]
       }
    }
}

I considered doing this at runtime, but it makes much more sense to have this happen once at build time.

[enhancement]