Support listing and deleting wasm databases

[simolus3]

This adds the WasmDatabase.probe API, which can be used to list existing databases and delete them. It can also be used to open a database with a specific storage implementation which can be useful for apps needing a higher degree of customization.

@FaFre Feel free to take a look at the API to see if would satisfy your requirements. Unfortunately we can't efficiently iterate through IndexedDb databases, so we can only give you a complete list of OPFS databases.

[github-actions]

🚀 Deployed on https://deploy-preview-2554--moor.netlify.app

[FaFre]

Wow! That's great 🤩
It perfectly fits my needs, thanks for recognizing my feedback.

To give some feedback after switching to this implementation:

• I created an extension to easily get my desired implementation:

extension _ on WasmProbeResult {
  WasmStorageImplementation? getPreferredImplementation() {
    if (availableStorages.contains(WasmStorageImplementation.opfsShared)) {
      return WasmStorageImplementation.opfsShared;
    } else if (availableStorages
        .contains(WasmStorageImplementation.opfsLocks)) {
      return WasmStorageImplementation.opfsLocks;
    }

    return null;
  }
}

• I also decided to cache WasmProbeResult to open several databases from this instance. I hope to squeeze a bit of performance out of this, because my users will swap databases quite often.

[simolus3]

Caching the result is probably a good call - I don't want to do it in drift because the list of existing databases could have changed, but it good to do it when you know they haven't. We have to re-run the whole feature detection chain every time which tries to spawn workers, so it's not exactly cheap (doing it once is fine though).