ci: refactor ci jobs

What does this MR do?

This is a small refactor of the current CI jobs with a few improvements:

• properly configured cache policy (push during download-deps, pull otherwise)
• Stageless pipelines (See gitlab#30632 (closed) and https://about.gitlab.com/releases/2021/08/22/gitlab-14-2-released/)
• exclude eslint using SAST_EXCLUDED_ANALYZERS
• use matrix for Go versions
• make cisetup for CI

Closes #610 (closed)

TODO

• I added the Changelog trailer (e.g. Changelog: feature) to the commits that need to be included in the changelog
• I added unit tests or they are not required
• I added acceptance tests or they are not required
• I added documentation (or it's not required)
• I followed code review guidelines
• I followed Go Style guidelines