In an attempt to make our package naming more understandable we move all
our packages to a single NPM scope. `automerge` ->
`@automerge/automerge` and `automerge-wasm` ->
@automerge/automerge-wasm`
JS packaging is complicated and testing it manually is irritating. Add a
tool in `automerge-js/e2e` which stands up a local NPM registry and
publishes the various packages to that registry for use in automated and
manual tests. Update the test script in `scripts/ci/js_tests` to run the
tests using this tool