Merge branch 'tor/new-diffs/docs/next-streamed-files' into 'master'

Move the backend streamed files chart into the blueprint

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149787



Merged-by: Mireya Andres <mandres@gitlab.com>
Approved-by: Mireya Andres <mandres@gitlab.com>
Co-authored-by: Thomas Randolph <trandolph@gitlab.com>