Allow (Inherited) Folder Restriction In Data Object/Document Tree

[solverat]

Q	A
Bug report?	no
Feature request?	yes
BC Break report?	no
RFC?	no

• Allow to set restriction on folder layer within data object / document tree
• Set inheritable as default (checked, read only - same as restricted asset folders)
• Check if children are valid candidates (based on allowed_objects for data objects, and page for documents)

[blankse]

@solverat I created a PR #191