Add option for `trust_remote_code=True` on transformers-cli download 
### Feature request

Currently is very convenient to download models using  `transformers-cli download`, however some models need an extra argument for `trust_remote_code=True`

for example 

`transformers-cli download "tiiuae/falcon-40b"`


### Motivation

Would it make sense to add

`transformers-cli download "tiiuae/falcon-40b" --trust_remote_code`

### Your contribution

PR
Sounds like a good addition to me! 

cc @sgugger who's been doing a lot of the work enabling remote code integration. <|||||>Yes, happy to review a PR!<|||||>thanks @amyeroberts and @sgugger , is there any other argument that worth adding and loading a model?