Redis pre-seed tool

RM9280

Implements a tool for interacting with Redis. Features include:

* Showing a count of VIFs with rules in Redis
* Showing a count of ports with groups in the database
* Showing a count of the total number of security groups in the database
* Cleaning up records in Redis that don't have corresponding records in
  database
* Writing all ports with security groups as VIF rule sets in Redis
Merge pull request #256 from Cerberus98/rm9280_merge

Redis pre-seed tool