rbac: initial commit.
rbac: fleshing out the overall structure...
rbac: clean up naming conventions.

don't introduce new cache keys in the depcache.
The tests still avoid hitting the db by pre-filling the depcache with data.
rbac: stremline test state setup.
rbac: look for roles recursively.
rbac: implement assign operations.
rbac: add schema.
rbac: rearranged predicates.
rbac: move tests into support/
rbac: provide rbac.
rbac: handle anonymous requests.
rbac: m_edge requires ints for Id, no names allowed.
rbac: lookup domain for name on anything.
rbac: user domain should be undefined for anon requests.