gitlab-ci: update cmake.org documentation in release package pipeline
Consolidate the CI jobs for cmake.org/cmake/help/git-{master,stage}
docs, and enable them in release package pipelines too.
Adopt Utilities/Sphinx/
changes that we previously kept on a private branch for generating the reference documentation on cmake.org
. Guard them with options activated only in the relevant CI jobs.
Backport: release:HEAD^2