Systems Refactor: LoadsSystem, @systems_map, etc.

[corymosiman12]

As part of the refactor to address #98, the Facility.@systems_map attribute was introduced. Previously, systems weren't well connected to the premises that they served. Initial testing was introduced in the Facility Spec (it mainly has to do with ensuring data is correctly imported from xml, not that the system information is applied correctly on simulation):

BuildingSync-gem/spec/tests/model_articulation_test/facility_spec.rb

Line 170 in 211ca8d

RSpec.describe 'Facility Systems Mapping' do

The testing still falls short. Known issues:

• A LoadsSystem does not get generated in the event systems are found. This leads to downstream errors when a loads system doesn't exist.
• LoadsSystem has a very 'OpenStudio' view of what this means. Includes information for: occupancy, internal loads, schedules, elevator. Is this what we want?
• The @systems_map doesn't get used as effectively as it could

A refactor of these should be done to better align BSync schema with OpenStudio concepts.