Add missing SpaceHeatingLoad and DomesticHotWaterLoad inputs and ExistingBoiler outputs

[adfarth]

Please check if the PR fulfills these requirements

• [ ] CHANGELOG.md is updated
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce?

(Bug fix, feature, docs update, ...)

Added:

• Previously missing SpaceHeatingLoad and DomesticHotWaterLoad inputs: addressable_load_fraction
• Previously missing ExistingBoiler outputs: year_one_thermal_to_tes_series_mmbtu_per_hour and year_one_fuel_consumption_series_mmbtu_per_hour

Removed:

• ExistingBoiler output: thermal_to_tes_series_mmbtu_per_hour, year_one_fuel_consumption_mmbtu_per_hour, year_one_thermal_production_mmbtu_per_hour

What is the current behavior?

(You can also link to an open issue here)

What is the new behavior (if this is a feature change)?

• Add addressable_load_fraction inputs (and validation) for SpaceHeatingLoad and DomesticHotWaterLoad which effectively ignores a portion of the entered loads. These inputs can be scalars (applied to all time steps of the year), monthly (applied to the timesteps of each month), or of length 8760 * time_steps_per_hour.
  • We handle the alignment of addressable_load_fraction and the fuel input (annual_mmbtu, monthly_mmbtu, or fuel_loads_mmbtu_per_hour) in REopt.jl Julia package.

Does this PR introduce a breaking change?

(What changes might users need to make in their application due to this PR?)

Other information: