Enhance Patient/$everything to support 0..* cardinality _id parameter.

[tadgh]

It would be helpful to have parameters for Patient/$everything which would allow us to qualify a set of patients which we cared about $everything for.

How about we mimic normal search, and add an optional _id search param to Patient/$everything.

Patient/$everything?_id=id1,id2,id3

Also, support repeating of the _id param as parameters can be posted:

Treat Patient/$everything?_id=id1&_id=id2&_id=id3 is the same as Patient/$everything?_id=id1,id2,id3