Removes dependence on instance ID for all monitoring logic

[autodidaddict]

Since instance ID will always be "n/a" on the new 0.60 heartbeats, this removes reliance on instance IDs for building the observed model.

[autodidaddict]

Testing methodology:

• Updated unit tests to reflect the no-longer-unique nature of the instance ID
• Started a lattice observer against the default lattice
• Started two hosts on the lattice
• Added, removed providers and actors and watched the observer properly reflect the lattice state

[autodidaddict]

Addresses #25