refactor(developer): compiler interface part 1 for wasm

This starts the refactor of the .kmn compiler interfaces for WASM,
moving more file writes into typescript and out of the compiler. Adds a
cleaner binding and structures for passing compile metadata back to
typescript for additional build steps (e.g. kvk, js builds).

Will rebase the Typescript-based KMW compiler onto this so it can start
to benefit from the refactoring.

* Fixes a minor issue with loading a .kvks file with an empty flags set.
* Adds a writeFileSync method to the compiler callback interfaces.
* Adds an e2e compiler test to verify that .kmx and .kvk are both
  correctly compiled.