Publish docker images on release

[jeffa5]

Is your feature request related to a problem? Please describe.

The docker images would be useful to have published for allowing users to try out the service locally more easily.

Describe the solution you'd like

Automatically publish the docker images on a tag.

Describe alternatives you've considered

Let users build the images themselves, but why make their machines burn cycles?

[jeffa5]

Currently, we publish the images on pushing to main under ccfmsrc.azurecr.io/public/lskv:latest-${target} for targets virtual and sgx.