Create "modules" that run when a package is reported

[jonathan-d-zhang]

We want the ability to run code (@import-pandas-as-numpy is calling them 'modules') in response to a package being reported.
 
Requirements:

• Should not run as part of existing services (any issues with modules shouldn't impact existing Dragonfly services)
  • Also means that it should be outside Dragonfly's review + release cycle like the Yara rules
• These modules will have the package being reported as an input (the actual format of this input is not specified).
• The modules will produce some arbitrary output, such as posting to a webhook or writing to a database.
• The modules will be written in Python.

An idea: use a message queue and Pub/Sub and make reporter one of these modules. Other modules would simply Sub to the Pub in order to register themselves.