Create a per-provider Turtle file to describe the provider

[kjetilk]

Per the discussion in solid-contrib/information#16 , we should make a Turtle file per provider, where the provider may describe themselves and their policies. They could then submit their URL to POD provider registries and it could then be scuttered to provide such a list.

[megoth]

Should we expand the Solid vocabulary or are there existing vocabularies that might cover our need?

[kjetilk]

Not sure, but I think we can use a lot from Dublin Core and friends.

[megoth]

Perhaps the resource describing the provider should be a virtual resource, and be automatically generated? I reckon trustedOrigins could be an interesting list to expose (cf #1090)?