Add additional URL attributes to openid client

[cunio-martin]

Hi @mrparkers ,

I really appreciate your TF provider, it make managing KC installations so much easier!

One thing that I currently miss are some additional attributes in keycloak_openid_client. In the UI there are additional URLs that you can specify in the Oauth consent screen

It would be very nice if those can be specified in the tf files, for the moment I will enhance them manually. Unfortunately I'm not too experienced with writing TF provider but if I find some time in the next months I might fork it and create a MR but quite likely you're much faster adding these three attributes directly ;-)

Cheers, Martin