CNG: Dissolve gitlab-go into the builder image

Opportunity

When gitlab-go is not used as the base image (see #3449 (closed)) it no longer needs to be an individual image. Go language compiler and tools can be moved to a builder image (as proposed in #3444 (moved)) which is shared in the build stage across all images. By doing this we can remove the gitlab-go image and its jobs from pipeline and simplify other images.

Proposal

• Move Go language compiler and tools into the builder image
• Remove gitlab-go image and replaces it with the builder image

For Debian-based images this depends on both #3449 (closed) and #3444 (moved) but it can be done for UBI-based images with their current state.