Feature Request: Add the MediaPipe's Face Mesh model

[tawichi]

Hi!
Thank you for your work!
I have a feature request for a face mesh model.
MediaPipe FaceMesh can detect 468 3D key points and is widely applicable to face analysis.
FaceMesh is licensed under the Apache 2.0 license. Pre-trained models are available and can be easily integrated into Facetorch.
I would appreciate it if you would add this model.