Consolidate neighbor count logic

[kmcginnes]

The logic around discovering and collating neighbor information is spread out across the code base. On my prior attempts to make graph reloading from IDs work this was a major bottleneck.

The task is to pull out all the logic around neighbor calculations to a single place and integrate it with display entities for just the graph canvas and table. This allows the gathering of the information to be deferred and ensures consistent behavior.

It may even end up with better performance.