deprecate %app

deprecate %app

* module/ice-9/boot-9.scm (module-name): Don't rely on (%app modules),
  use other tricks to name anonymous modules.
  (resolve-module): Instead of relying on %app, close over the root of
  the module hierarchy -- the module that was '(%app modules).

* module/ice-9/deprecated.scm (%app): Provide a compatible %app shim.