Update the links in all docs except user and admin pages

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/421591

Follow-up for
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/132111

* Remove `Gitlab::RuggedInstrumentation`
* Remove `Peek::Views::Rugged`
* Remove lint-rugged script
* Adjust tests and documentation

Changelog: removed

The cloud_connector team is not actively working on reducing memory
requirements. Sentence is being removed to reflect the reality.

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/421591

Rugged patches were disabled in 16.5:
https://gitlab.com/gitlab-org/gitlab/-/issues/425260.

It's time to update the documentation to reflect the current state.

updating installation requirements to the suggested 12 GB of storage available and 1GB of vulnerability data

Updates from review

Also refactor upgrade paths section.

Changelog: changed
Signed-off-by: Balasankar "Balu" C <balasankar@gitlab.com>

Documentation updated to show Redis 6.0 as a requirement instead of
Redis 5.0 in both Omnibus installation and reference architecture
instructions.

This removes all references to Puma Worker Killer,
which is not used anymore.

Our style guidelines say not to use
https://docs.gitlab.com/ee/development/documentation/styleguide/word_list.html\#eg

Related epic: https://gitlab.com/groups/gitlab-com/-/epics/1940

We don't want to duplicate nav items
So this MR moves content into a new
page

Although there are limitations and potentially stability and performance
concerns running puma in single mode has no data integrity problems as
far as is known. The current message raises concern with the way it is
phrased, so change the phrasing to avoid this implication.

See also the originating discussion for details:
https://gitlab.com/groups/gitlab-org/-/epics/5303#note_1016292201

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/342093

Related to group: Distribution

Changelog: fixed

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

In https://gitlab.com/gitlab-com/www-gitlab-com/-/merge_requests/104673,
we split the Enablement stage into Systems and Data Stores. This commit
changes the Distribution and Geo groups to the Systems stage.

Make sure that the rest of our docs reflects the upcoming change
in PostgreSQL versions.

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>