Metrics collection

This script will collect a DC's total desired and actual when run. 

**TODO**:
- [ ] Collect pending also
- [ ] Tests
- [ ] Dump the data to Cloud metrics
Agreed, thank you for clarifying the purpose of this function  :)  I did not state that very clearly in the previous comment.  However, I was thinking an we not just do filtering, but split the data into multiple data sets or transform the data (split into pending/active/error, or just count the number in each), which was why I was thinking it could be another function that gets composed over this one.