Python Script Update

[catherinemeadows]

Summary:

The Python script for starting up a chain of NFs was using time.clock() which was deprecated in Python 3.3 so running the script gave an error. I updated to use time.perf_counter().

Usage:

This PR includes
Resolves issues
Breaking API changes
Internal API changes
Usability improvements
Bug fixes	👍🏼
New functionality
New NF/onvm_mgr args
Changes to starting NFs
Dependency updates
Web stats updates

Merging notes:

• Dependencies: None

TODO before merging :

• [X] PR is ready for review

Test Plan:

Ran script with example JSON file and ensured that it timed out correctly for the defined TTL.

[twood02]

@catherinemeadows you can merge this if it allows you to