packages section is optional in the CBA, however, code has a bug such that the virtual env for python won't get setup (as it's tied to package installation).

As result, there is a reference to (non-existant) activate_this.py during the execution phase, which results in an exception being thrown and only a gRPC exception relayed back to blueprints processor which has nothing to do with the original error.

This bugfix improves the error handling during env.prep phase. 
During the execution phase, checks if the environment doesn't exist create it (would work for no package install case)
Reworked function calls from returning True/False status to return a struct with the status as well as the err_msg (in case there's any) so that actual cause can be bubbled up back to the user.

The original error msg returned was 

ERROR
- Exception calling application: 'bool' object is not subscriptable