Don't send nginx config when image versions mismatch

[sjberman]

During an NGF upgrade, the new version of the control plane will send a configuration to the old version of the nginx data plane, before the nginx data plane is updated to the new version. This can cause incompatibility issues for a brief amount of time, which could cause disruptions.

Our control plane should not send configuration if it detects that the version of the data plane pod is different from what it expects. The version it expects will either be defined in the image settings of the NginxProxy resource, or as a default value. When the control plane first gets a connection from a data plane and gets the pod's owner, it should also get its container image, so that it can verify that it matches before sending a config.

Acceptance Criteria

• if control plane detects that a connected nginx data plane pod has a version different from what it expects, do not send it any configuration