Use a standard HTTP response for the jackson service

[niwsa]

Currently we send the response payload back as either json or plaintext. It would be better to standardise the format into JSON with defined structure for error and data. Eg:- Error

{
 "status": 400 
 "error": {
  msg: "Please provide a defaultRedirectUrl" , 
  description: "Jackson needs the URL to complete the IdP flow"
 }
}

Success

{
"status": 200
"data": {
      client_id: clientID,
      client_secret: clientSecret,
      provider: idpMetadata.provider,
  }
}

[niwsa]

UPDATE: This issue is mainly to standardise the error response sent out from jackson service. Endpoints /oauth/authorize and /oauth/saml handles most errors by redirecting to the client redirect_uri. The endpoints /oauth/token and /oauth/userinfo can follow the spec as listed below.

Token endpoint - https://datatracker.ietf.org/doc/html/rfc6749#section-5.2 Userinfo endpoint - https://openid.net/specs/openid-connect-core-1_0.html#UserInfoError and https://datatracker.ietf.org/doc/html/rfc6750#section-3.1