Add API support for Passkeys

[jan-tennert]

What kind of change does this PR introduce?

Feature (closes #1234)

What is the current behavior?

No passkey support

What is the new behavior?

New passkey support under supabase.auth.passkeys. Syntax:

val response = auth.passkeys.startRegistration()
println(response.options)

val response = auth.passkeys.verifyRegistration(myChallenge, myEncodedCredential)
println(response.friendlyName)

val response = auth.passkeys.startAuthentication { 
    captchaToken = "optionalCaptcha"
}
println(response.options)

val response = auth.passkeys.verifyAuthentication(myChallenge, myEncodedCredential)
println(response.session)

val passkeys = auth.passkeys.list()
println(passkeys)

auth.passkeys.update(myPasskeyId, "Really friendly name")

auth.passkeys.delete(myPasskeyId)

Native support will come once #1291 has been figured out. So for now only the API methods.