Split into one main page and two tutorials.

Update offering notes with all three offerings

Related to: https://gitlab.com/gitlab-org/gitlab/-/issues/439130

Scoping down to a subdirectory should help us move these through
more quickly. Or, at least, do more sensible levels of search-and-
replace.

Makes use of markdownlint for automated cleanup

Because for now, we're changing the format.

Related to: https://gitlab.com/gitlab-org/gitlab-docs/-/issues/1751

Align columns and sort alphabetically

Update the links in all docs except user and admin pages

This is not used on the current docs website
and needs to be removed for future compatibility
with Hugo.

Because we changed the way we
do the markdown.

Related to: https://gitlab.com/gitlab-org/gitlab-docs/-/issues/1690

Ensure all tables are consistent and following current
standards in the API docs, to make future contributions
easier.

Fixes incorrect expiration date extraction from .cer and .p12 files uploaded to Secure Files.

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/119805

Pipeline Insights becomes Pipeline Security, and
many categories shifted around.

The project-level secure files API now returns file metadata in the API response for supported file types.

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/102639

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

The permissions attribute in the Secure Files model is not used and has been removed.

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/86598

The Secure Files API now requires that all files in a project have unique file names

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/83628

The checksum validation option has been removed from the Secure File POST endpoint.

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/84314

The Secure Files POST endpoint now supports an optional file_checksum
param which validates the request against a sha256 checksum of the
uploaded file. The validation does not run if no value is supplied.

Changelog: changed