Support new implementation for requesting claims in selective disclosure

[ugoamanoh]

What's here

Added a new claims param to the payload when making selective disclosure requests. This keeps us up to date with the latest changes in the specs Selective Disclosure Request
Created a helper class to make it easier for developers to create claims while making requests

Testing

Run the gradle command ./gradlew test cC --no-parallel

[mirceanis]

I made a few suggestions.

In a way building request using maps directly looks cleaner.
I would love it if we could come up with a DSL with the same look and feel but with proper type checks.

This PR works from a type safety perspective but I think we can make it a little more usable.

I'm thinking of something along these lines:

val claimsReq = ClaimsRequest()
.requestCredential("email") {
    issuedBy("did:web:uport.claims")
    issuedBy("did:web:sobol.io", "https://sobol.io/verify"))
    essential false
    reason "To contact you with regard to your account"
  }
.requestUserInfo("name") {
    essential true
    reason "To show your name when you are logged in"
  }

Then, to keep type safety all the way through, the SelectiveDisclosureParams can accept ClaimsRequest object instead of generic Map<String, Any> and perform the conversion to a payload map in buildPayloadForShareReq

What do you think?

[mirceanis]

Since this requires a call to build() to be used in a request, it makes sense to call it ClaimsRequestBuilder or something along those lines.
This class does not encapsulate the params themselves.

[mirceanis]

since the claims field does not get modified later on, there is probably no need to make it mutable here.

Suggested change

	payload["claims"] = params.claims.orEmpty().toMutableMap()
	payload["claims"] = params.claims.orEmpty()

[mirceanis]

The claims param makes the other ones obsolete.
Should we print out a warning when claims param is used along with requested and verified ?

[mirceanis]

since UserInfoParams can only be used in this context, it makes sense to have the parameters be directly passed to the .addUserInfo() method.
This call would then look like this:

Suggested change

	.addUserInfo("name", UserInfoParams("Show your name to other users", true))
	.addUserInfo("name", "Show your name to other users", true)

It is a bit more concise and can provide the same parameter type safety

[mirceanis]

in a way, this way of building the request looks cleaner.
I would love it if we could come up with a DSL with the same look and feel but with proper type checks