Upgrade SAM's URDB query to URDB version 8, and connect the relevant demand charge lookback features to the new billing demand inputs in SAM.

• https://openei.org/services/doc/rest/util_rates/?version=8
• lookbackRange corresponds to ur_billing_demand_lookback_period
• lookbackPercent corresponds to the first column of ur_billing_demand_lookback_percentages
• Unfortunately lookbackMonths might be ambiguous. It could either correspond to a 0 value in ur_billing_demand_lookback_percentages, or it could correspond to a time of use period in ur_dc_billing_demand_periods