Simplify nodeshot.networking models

[nemesifier]

This is a hard one.

The models in nodeshot.networking.net, nodeshot.networking.links, nodeshot.networking.hardware feel to complex to work with. The model design was influenced by comparing with node-dbs of other community networks so that the designs would be similar. Unfortunately this caused unnecessary complexity. Features can be added later, if at all needed.

We need to:

Simplify models

• fewer relations
• coupled django apps should probably be merged into a single app

Drop unimplemented features

• planned links