Add ability to upload template to S3

[jdavidbakr]

I'm running into an issue as my template has apparently exceeded the limit for submitting it via the command line. I'm getting the following error when trying cpack build and cpack deploy:

Member must have length less than or equal to 51200

It would be fantastic to be able to upload the template file to S3 and then use that in the cloudformation deployment process.

[jdavidbakr]

As a workaround I am bale to do cpack build --no-validate and manually upload the resulting json file to CloudFormation. Ideally, though, cpack deploy should handle this.