Move knowledge-base to SOP
Solves https://gitlab.com/gitlab-com/support/issues/331
- Move
/knowledge-base/
to/sop/
- Remove categories
- Update Support Handbook links
//c @ernstvn
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Solves https://gitlab.com/gitlab-com/support/issues/331
/knowledge-base/
to /sop/
//c @ernstvn