Offer mutliple wasm builds depending on media content

**Is your feature request related to a problem? Please describe.**

The wasm file is very big because all of the decoding libraries are in there. In our case we are using ffmpeg solely for audio content. I was thinking maybe its a good idea to offer different wasm builds: `full`, `video`, `audio`, `image`.

**Describe the solution you'd like**

Offer different wasm builds which fit for certain usecases:
- `full` the same wasm build as of right now with everything in there
- `video` a wasm build which only has libraries which can be used for video content
- `audio` a wasm build which only has libraries which can be used for audio content
- `image` a wasm build which only has libraries which can be used for image content

**Describe alternatives you've considered**

I didn't consider any alternatives besides searching for smaller libraries than `ffmpeg.wasm`