Merge branch '353031-docs-add-secure-consul-docs' into 'master'

Add Secure Consul documentation

Closes #353031

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/157754



Merged-by: Achilleas Pipinellis <axil@gitlab.com>
Reviewed-by: Achilleas Pipinellis <axil@gitlab.com>
Co-authored-by: Jon Doveston <jdoveston@gitlab.com>