Use different name for FIPS packages

Even though we originally thought to use gitlab-fips as the package name for FIPS packages, in #6576 (comment 840046217), we decided to reuse gitlab-ee as the package name for FIPS builds, as it was the easiest way to run QA (gitlab-qa only understands gitlab-ce and gitlab-ee as image names). However, based on discussions in the FedRamp working group, we might want to differentiate EE and FIPS packages even more, which means we should go back to gitlab-fips as the package name.

Note: This would require changes to GitLab QA project to support image names other than gitlab-ce and gitlab-ee. It should support gitlab-fips as an image name, but consider it to be synonymous with gitlab-ee (in selecting which all tests to run).