ALBANY — The state is offering a seven-year plan to redevelop some or all of the mostly-deserted land in downtown Albany that was once envisioned for a new convention center.Released Thursday to the Albany Convention Center Authority, the plan from Empire State Development envisions a 1 million square-foot mix of residential, retail, and entertainment projects, and potentially a hotel, all of which could done in phases.The report did not estimate how much it might cost to redevelop the 8-acre parcel — which includes the former Adirondack Trailways bus station, several vacant commercial buildings, and open parking lots.