Allow mint to a different address than users

[amiller]

This feature is part of "frontend abstraction", allowing different front ends by relying only on TEE delivered backend to make sure users are shown what they are about to approve.

Right now this line prevents the address in the query from minting to any other recipient than the logged in users themselves

teleport-gramine-rs/src/endpoints.rs

Line 229 in 024ba60

if session.x_id != user.x_id.clone().unwrap() {

To fix this,

• have a separate queury variable, a second optional address for "recipient" that can differ than the user address
• mint to this address instead