Port update methods to Attean

[kjetilk]

RDF::Trine::Store::SPARQL has support for quads and for updating the remote graph. This would be great to have for AtteanX::Store::SPARQL too. Essentially, doing so would be a port, and what's involved is, I think, to make AtteanX::Store::SPARQL an implementation of Attean::API::MutableQuadStore and make the tests also support quads. It is a relatively large job, but shouldn't be a very difficult one, given the implementation in RDF::Trine::Store::SPARQL.