Adds ability to throw/catch/rethrow exceptions in MuranoPL

The syntax is
Try:
  - Throw: ns:name   #can be list of names to simulate type hierarchy
     Message: message   #optional
     Cause: $sourceException   #optional
     Extra: { 'someExtra': 'data' }    #optional
Catch:
   - With: ns:name #can be list of names
   - As: exception   #optional
   - Do:
        - Rethrow:
Else:    #optional
    - else block
Finally:    #optional
     - finally block

Improves stack traces to contain information about Python native stack frames and macro blocks

Change-Id: I2e2bcc5e1a0da5f9489d73525f8b3fa99cc0220c
Implements: blueprint muranopl-exception-handling
Merge "Adds ability to throw/catch/rethrow exceptions in MuranoPL"