Fix oauth flow and remove go-oidc library (#1063)

- Update transport to use the same from Console in IDP Auth
- Validate provided idp URL

Co-authored-by: Harshavardhana <harsha@minio.io>
Signed-off-by: Ricardo Katz <rkatz@vmware.com>
Signed-off-by: Lenin Alevski <alevsk.8772@gmail.com>

Co-authored-by: Ricardo Katz <rkatz@vmware.com>
Co-authored-by: Harshavardhana <harsha@minio.io>

swagger-operator.yml

@@ -1358,13 +1358,10 @@ definitions:
         type: object
         required:
           - configuration_url
-          - url
           - client_id
           - secret_id
           - claim_name
         properties:
-          url:
-            type: string
           configuration_url:
             type: string
           client_id: