batch: Provide option to bypass uploading workspace files

[bplotnick]

Uploading workspace files (including mounted files) runs the risk of uploading sensitive files like private keys. This was even called out in the original PR as a risk. There should be an option to bypass this.

Another option would be to only upload the filenames but not the file contents themselves. You could even have a .srcignore or something that would automatically skip these files

[stristr]

+1 to .srcignore— that would be an ideal implementation detail.