Added usesPkce() method to enable PKCE parameters and switched request options...
requested to merge issue/openid_connect_windows_aad-3266206:3266206-pkce-parameter-support into 8.x-1.x
Added usesPkce() method to enable PKCE parameters and switched request options to invoke parent request options from base (code is currently identical except for PKCE handling)
Closes #3266206