Add Torchvision and Torchaudio to base images (#1897)
* Exclude torchaudio from pip installs
* Use our torch audio from the cog base images
instead
* Install torchvision and torchaudio in base images
* Add the compatible versions of torchvision and
torchaudio to the base image python packages
* Include known packages into the requirements.txt
* Fix torch version modifiers in the requirements
* Set cog base image to false with no base image
* If we don’t find a base image explicitly set
this flag to false if it was ambiguous before
* This allows the rest of the script to continue
as if the user does not want a base image
