frontend: rc-tags for docker images

[DeltaMichael]

What is the feature request? What problem does it solve?

The current process for releasing frontend docker images is

1. data-pipelines and shared are created in the build stage
2. packages are published to the npm registry and docker registry in the publish stage
3. docker image pushed to registry and tagged with latest in the pre_release_image stage
4. docker image deployed to the test environment in pre_release_test stage
5. heartbeat probe, operability testing, etc. in the pre_release_test stage
6. docker image tagged as stable in the release_image stage

The process for releasing frontend docker images should be as follows.

1. data-pipelines and shared are created in the build stage
2. a frontend docker image with an rc tag is also created in the build stage
3. packages are published to the npm registry and docker registry in the publish stage
4. docker image deployed to the test environment in pre-release stage
5. image tagged as latest in the pre_release_image stage
6. heartbeat probe, operability testing, etc. in the pre_release_test stage
7. docker image tagged as stable in the release_image stage

Related to

That is clearly from previous change but do you know why is "frontend_deploy_testing_data_pipelines" part fo pre_release_test stage? It should be part of pre_release stage where the actual "pre-releases" like testing deployment are done ?

Originally posted by @tozka in #2359 (comment)