Slightly configurable backend-views

[Philosoft]

It'd be nice if we'd have a mechanism for configure backend pages like edit-product and edit-page. To be more specific:

• ability to create custom tabs
• ability to place predefined items (category tree, content-block, image-block etc) in those custom tabs

and all this right from that very page (edit-product/page).

Save this as settings:

• per user
• global settings (for all users)
• mb named sets - choices for users from predefined/shared custom sets