Restructure and Simplify Department Status Management and Delivery

[seekinginfiniteloop]

The current implementation that provides department statuses for time intervals is overly complicated and error-prone. I became enamored with the idea of an interval tree serving up this data. While optimal on paper, the subsequent translation to something usable counteracts this advantage while adding substantial complexity. We're also not dealing with noticeable performance differences given the size of the dataset.

I propose/plan a major restructuring on the backend, the principal aspects of which are:

• directly load constants.py data into pandas objects
  -ditch _tree and the interval tree delivery
• Add time-state and pandas index attributes to FedDepartment objects; add attributes that allow them to represent themselves as various pandas objects to facilitate easy construction
• Build a functional factory for FedDepartment objects.
• Tap this pool directly from FedIndex and FedStamp such they have these objects as attributes.
• build fedindex DFs directly from FedDept multi-index tuples