Authorization: Basic Base64Encode(client_id:client_secret)
Authorization: Basic bXktYXBwOm15LWFwcC1zZWNyZXQtMTIz
POST /realms/EDVAK/protocol/openid-connect/token
Content-Type: application/x-www-form-urlencoded
code=abc123&
code_verifier=xyz456&
grant_type=authorization_code&
redirect_uri=https%3A%2F%2Fexample.com%2Fcallback&
client_id=my-public-client