Option to exit with an error if dependencies could not be packaged

When a dependency fails to be packaged, Chalice prints the following:
```
Creating deployment package.

Could not install dependencies:
...
You will have to build these yourself and vendor them in
the chalice vendor folder.

Your deployment will continue but may not work correctly
if missing dependencies are not present. For more information:
http://aws.github.io/chalice/topics/packaging.html
```
When this is used in an automated deployment pipeline, any dependency update can result in a broken deployment. (In our case, this was exacerbated because certain dependencies install fine on Linux, but fail to install on Mac when packaging wheels cross-platform, and this fail changes from version to version of upstream dependencies, depending on the wheels they have uploaded to PyPI.)

It would be nice if Chalice could just quit with an error when this happens, instead of producing a broken deployment.

The issue names no source files or tests. Start by tracing Chalice's dependency-packaging path and CLI deployment flow, using the packaging documentation linked in the report; identify where packaging failures are currently reported, then verify that the new option stops automated deployment while preserving the existing default behavior.

Written by the indexing model from the issue text.