Generate the Route certificate using the specified issuer

[leochr]

Liberty Operator supports bring-your-own certificate for Route using a secret. This secret must be created and specified by the user. With Cert Manager such a secret could be created using a Certificate CR. The Operator could create the Certificate for the user using the issuer information (name and kind Issuer/ClusterIssuer). To avoid escalating the Operator's permissions, it shouldn't look up the ClusterIssuer. Instead, just make the Certificate request, check the Certificate status and/or creation of Secret and specify it on the Route.