- add temporary function to Core for this POC
- add new CoreProcessor to access Keyman Core WASM
- add unit tests for new core processor
- add code to KeymanEngine and InputProcessor to load the new CoreProcessor
- add web server to manual tests and new action `start` to build script
This change requires the manual tests to be loaded from a web server
instead of loaded as file, because otherwise the wasm code won't be
loaded.
Currently we always load CoreProcessor. This should be improved in a future
change to only load when it is actually needed.
Part-of: #11293
