Introduce preferredURI for profile

[csarven]

Currently under "edit websites", the user input text "webid" maps to http://www.w3.org/2002/07/owl#sameAs. While that's not particularly wrong, the object in question could be away from user's control. That is, people have profiles around the Web, and not all of them are created or under their direct control.

In order to take intended WebID profiles into account, ie. profiles that are more likely to be under a person's control that an ORCID profile can refer to, http://www.w3.org/2000/10/swap/pim/contact#preferredURI may be more suitable than the generic http://www.w3.org/2002/07/owl#sameAs.

I think owl:sameAs is still very useful to keep around.

Proposal for the input text from the UI and the generated mapping:

• "sameas" maps to owl:sameAs
• "webid" maps to contact:preferredURI

The only issue with this is that existing ORCID profiles that currently use the term "webid" needs to be updated and replaced with "sameas", in order to keep the existing desired mapping to owl:sameAs that people wanted in the first place. Can this be a batched process? Any statistics on how many people use "webid" - I'm guessing not a whole lot.

The contact:preferredURI value is expected to be a string (whereas owl:sameAs is a URI). A PR for this issue should take that subtle difference into account.