Revise taxes for class 17 data center property (HB 424, MT)

Extends building timeframe for data centers to qualify for tax breaks; stipulates that data center excess electricity can’t be sold to utility for profit; backup generators count towards property requirements for tax break eligibility; provides ongoing discounted (but higher) property tax rates for generators after first 10 years, requires local school funding tax be paid; reduces period that data center communications infrastructure receives very low tax rate.