[FEATURE REQ] Use buildx instead of build to build modules

### Description.

Looks like `iotedgedev` uses `docker build` in shell script files under the hood.

Docker has moved to use BuildKit and AFAICS `build` is deprecated and will eventually be completely gone. Using it already causes warnings about this.

It doesn't look like replacing `build` with `buildx` would be much effort at all, so how about doing that?