### Description

Adds opencv-python and ffmpeg.

### Status

opencv-python is modularized with a bunch of modules, I'll keep updating the status.

- [x] Core library
- [x] JPEG
- [x] PNG
- [x] WEBP
- [x] Image processing
- [x] video processing (FFMPEG)
- [x] objectdetect
- [x] dnn
- [x] ml
- [x] calib3d
- [x] feature2d
- [x] highgui (built, but nonsense)
- [x] photo
- [x] stitching
- [x] flann
- contrib algorithms?
- extra modules?

### Checklists

<!-- Note on checklists:
     If you think some of these steps are not necessary for your PR,
     just remove those checkboxes, or mark them as checked. Otherwise,
     if some checkboxes are left unmarked, we might assume that your PR
     is not ready to be merged and we might keep you waiting -->

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests

Resolve #381
Resolve #1627
PKG Add opencv-python and ffmpeg. ### Description

Adds opencv-python and ffmpeg.

### Status

opencv-python is modularized with a bunch of modules, I'll keep updating the status.

- [x] Core library
- [x] JPEG
- [x] PNG
- [x] WEBP
- [x] Image processing
- [x] video processing (FFMPEG)
- [x] objectdetect
- [x] dnn
- [x] ml
- [x] calib3d
- [x] feature2d
- [x] highgui (built, but nonsense)
- [x] photo
- [x] stitching
- [x] flann
- contrib algorithms?
- extra modules?

### Checklists

<!-- Note on checklists:
     If you think some of these steps are not necessary for your PR,
     just remove those checkboxes, or mark them as checked. Otherwise,
     if some checkboxes are left unmarked, we might assume that your PR
     is not ready to be merged and we might keep you waiting -->

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests

Resolve #381
Resolve #1627
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name: Code improvement
about: Suggest a code improvement, i.e. refactoring, deprecation, etc.
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