refs #5614, #5943
- adds a new 'filter' bookshelf plugin which extends the model
- the filter plugin provides handling for merging/combining various filters (enforced, defaults and custom/user-provided)
- the filter plugin also handles the calls to gql
- post processing is also moved to the plugin, to be further refactored/removed in future
- adds tests showing how filter could be abused prior to this commit
refs #5614
- change isPublicContext to detectPublicContext
- behaviour now expands the context object out
- this is a bit of a sideeffect, but this is the simplest change
that makes it possible to use the context in the model layer without
significant wider changes
- add new access rules plugin
- takes a context object as part of `forge()` & caches it on the model instance
- provides helper functions for testing access rules later on
