[WIP] SMITH
# What does this PR do?

This PR adds SMITH encoder by Google Research and potentially closes #9526.

Potential reviewers:
@LysandreJik @patil-suraj
Hi @gchhablani 

What is the state if this PR ?

Have you tried loading [the official SMITH checkpoint](https://github.com/google-research/google-research/tree/master/smith#pre-trained-model-checkpoint) ?

Amine<|||||>Hi @amineabdaoui

I had tried it a while back and it had worked. My focus switched to other things. I'll get back onto this PR this week.