More types of requirements

[michielbdejong]

We have ClassFileRequirement, PodWideRequirement, and ContainerBoundrequirement.

We need to add:

• profile document (i.e. doc the webId resolves to)
• global inbox
• specific attribute of the profile, e.g. as:following collection
• inbox of a given document, e.g. of the as:following collection
• setting up an ACL that gives a vcard:Group G some mode access to resource R
• generalize the ContainerBoundrequirement so that it doesn't hard-code a path?
• (reading) preferences
• (reading) private type index

[michielbdejong]

These requirements can be added together to define the required access scopes of an app. They obviously tie in with interoperable data discovery.

[michielbdejong]