Migrate build of container to egeria-ui project

[planetf1]

Currently the container image for the static content is built under the main egeria project as part of the maven merge build running under azure pipelines

I propose we move the container build here, so that it is consistent with the code it contains.

• Look at if we can do this under github actions
• will need access to the odpi credentials for accessing the repo
• we could initially push to the github container repo for testing
• we could look at whether even a PR could build the container (for verification and testing) - and use a PR specific 'tag'

There is still code in egeria repo that references the image - docker compose & lab helm chart. If the name of the image, location, or version changes, this will need updating.
Two changes we've not done yet in egeria for this image

• verifying image security.
• Using a UBI image (we do use the redhat UBI-8 image for base egeria, hopefully can use the same for the UI)
• ensure we always use https

[sarbull]

@planetf1 can this be closed?

[sarbull]

i updated the README file to align the fully decoupling of the UI from the Backend, we can start with HTTPS with polymer-cli if needed, i managed to start it with a custom certificate

[planetf1]

yes this can be closed now.