ptp-operator: Consistent ghcr.io release images and file-based catalog

[lack]

In order to make use of the upstream operator more straightforward, we should:

• ensure we're publishing latest images of ptp-operator with references to relevant linuxptp-daemon and cloud-event-proxy upstream images so it can be used out-of-the-box
• Publish a file-based catalog for use with OLM for ease of installation with OpenShift and OkD

In the short term, we should focus on getting this right for :latest builds, but then as a follow-on we could address #159 and start publishing more formal versioned releases as well.