The JS package is now written in typescript so we don't need to manually
maintain an index.d.ts file. Generate the index.d.ts file from source
and ship it with the JS package.
By moving to wasm-bindgens `bundler` target rather than using the `web`
target we remove the need for an async initialization step on the
automerge-wasm package. This means that the automerge-js package can now
depend directly on automerge-wasm and perform initialization itself,
thus making automerge-js a drop in replacement for the `automerge` JS
package (hopefully).
We bump the versions of automerge-wasm
We add a script for running the js tests in `scripts/ci/js_tests`. This
script can also be run locally. We move the `automerge-js` package to
below the `automerge-wasm` crate as it is specifically testing the wasm
interface. We also add an action to the github actions workflow for CI
to run the js tests.
