decouple connected-solid from WAC

[elf-pavlik]

Solid Protocol currently includes both WAC and ACP. Linked Web Storage could pick one, both, or even select another system. It would be useful not to assume WAC and keep authorization system clients loosely coupled.

[jaxoncreed]

I hope to do this when there's a access control overhaul for LDO. At the moment it's a low priority, but if you said "ACP support" was one of the requested features, it would be a high priority!