President Trump on Monday sent Congress a $4.4 trillion budget with steep cuts in domestic programs and entitlements, including Medicare, and large increases for the military, envisioning deficits totaling at least $7.1 trillion over the next decade. The blueprint, which has little to no chance of being enacted as written, amounts to a vision statement by Mr. Trump, whose plan discards longtime  Republican orthodoxy about balancing the budget, instead embracing last year’s $1.5 trillion tax cut and new spending on a major infrastructure initiative.