[Recipe request] Add deep link recipe with DeepLinkKey interface #304

Currently, DeepLinkMatcher is the only official way to associate a key that supports a deep link to the type of deep link it supports. (i.e. UriDeepLinkMatcher associates the key : T with the url pattern it supports).

Developers may optionally want to colocate them, i.e.

interface DeepLinkKey {
    val uriPattern: String
}

data class UserKey(
    val id: Int
): DeepLinkKey {
    override val uriPattern: String
        get() = "www.nav3recipes.com/user/{id}"
}

Create a recipe showing such an interface and how to use it.