Merge branch 'jswain_add_identity_verification_documentation' into 'master'

Add documentation for Identity Verification

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/121592



Merged-by: Phillip Wells <pwells@gitlab.com>
Approved-by: Phillip Wells <pwells@gitlab.com>
Reviewed-by: Phillip Wells <pwells@gitlab.com>
Co-authored-by: Jay Swain <jswain@gitlab.com>