Add configurable routing plugins

[tkuester]

The parent issue for #26

taky should come with a few default plugins for routing packets, like filtergroups. However, users should also be able to "pip install" custom routing modules, and configure them in the server's taky.conf file.

This will need some architecture changes... here are some thoughts, with use cases.

This system will need the ability to...

• Have access the Configuration object to check configuration
• Install 3rd party plugins with pip
• Modify packets before sending them out (ie: Removing phone numbers, anonymizing location)
• Drop packets (ie: Refuse client-client data package transfers, rate limiting chat)
• Change how packets are routed (ie: Turning broadcast packets into group only packets)
• Add custom models for <detail> elements
• Access most parts of the system (ie: Able to check the client's SSL certificate to see if they have permissions to send certain packets)