feat: identity pattern and example

[harrysolovay]

A new pattern IdentityInfoUtil allows devs to more easily construct and decode identity info without thinking about the encoding/decoding of contained data types.

Before, we would have had to write this:

IdentityInfo(Rune.rec({
  display: Data.Raw13($.str.encode("Chev Chelios")),
  web: Data.None(),
  email: Data.None(),
  twitter: Data.None(),
  riot: Data.None(),
  image: Data.None(),
  legal: Data.None(),
  pgpFingerprint: undefined,
  additional: Rune.tuple([
    Rune.tuple([
      Data.Raw6($.str.encode("stars")),
      Data.Raw1($.u8.encode(5)),
    ]),
  ]),
}))

We can now write this instead:

const transcoders = new IdentityInfoTranscoders({ stars: $.u8 })

transcoders.encode({
  display: "Chev Chelios",
  additional: { stars: 5 },
})