Add Helm 3 to base image
In preparation for Helm 3 support for Auto DevOps, we need base images with Helm 3.
This is just the first iteration, it is possible we need to instead have both Helm binaries available from the same image.
See gitlab-org/gitlab#29038 (closed) and gitlab-org/gitlab#221187 (closed)
Edited by Hordur Freyr Yngvason