Revisit Endpoint/Handler/Manifest

[issa-tseng]

And likely reduce the amount the framework attempts to offer.

[issa-tseng]

Probably add a proper server/client application to janus-samples in support of this effort.

[issa-tseng]

It seems the interesting problems to be solved here are:

• (Thinly) formulating input to and output from a Janus system in a generalized way (in particular across server/client environments)
• Understanding when a Janus system is at equilibrium (and thus a server response can be formulated)
  • Relatedly, being able to elucidate the resources that created that equilibrium.
• Understanding and communicating exceptional cases, eg when a resource is unfetchable or a user hasn't permissions, and plumbing a meaningful descriptor of the problem out.

[issa-tseng]

Not interesting, of note, that presently exists in the code:

• Exact mappings of common errors.
• Any notion of PageModels, as distinct from generic ViewModels.
• A formal box from which to eg initialize Apps.
• Conformant syntax to particular routing syntaxes.