Merge branch 'link-to-install' into 'master'

Link source installation instructions in README.md

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183810



Merged-by: Achilleas Pipinellis <axil@gitlab.com>
Approved-by: Achilleas Pipinellis <axil@gitlab.com>
Approved-by: Kushal Pandya <kushal@gitlab.com>
Reviewed-by: Achilleas Pipinellis <axil@gitlab.com>
Co-authored-by: Anatoli Babenia <anatoli@rainforce.org>