Add gdict.py to operator/tools

gdict.py is a scriptable "key-values" store that uses google spreadsheets as storage and query.

More detailed description is in the usage information of the command.

This tool is a generalization of tools I've used for collecting m-lab server hardware and drac information, as well as some of the automation around the platform updates.  I believe that a scriptable key-values store like this is generally useful for operators.

This script is a dependency on the scripts that collect m-lab server hardware and drac information.