Merge branch '23_add-gitlab-workspaces-proxy-installation-to-docs' into 'master'

Add GitLab workspaces proxy installation to official docs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149996



Merged-by: Ashraf Khamis <akhamis@gitlab.com>
Approved-by: Vishal Tak <vtak@gitlab.com>
Co-authored-by: Cindy Halim <chalim@gitlab.com>