Fail gracefully on 'deploy' outside of project folder

**Repro:**
1. `chalice new-project helloworld`
2. `chalice deploy`

**Expected:** User friendly error message that the config isn't found like, "Error: Can't find chalice config. Are you in a chalice project folder?"

**Actual:** RuntimeError with stack trace occurs

It's confusing and frightening first time using.


Start by reproducing `chalice new-project helloworld` followed by `chalice deploy` outside the project folder, then trace the deploy command's missing-config handling. Done means the command reports that the Chalice config cannot be found and suggests using a Chalice project folder, without emitting a RuntimeError stack trace.

Written by the indexing model from the issue text.