A Buffalo non-profit that supports families out of homelessness is planning to build a new facility downtown.Family Promise of WNY has earmarked a Franklin Street parking lot as the site of a new facility, which would temporarily house 10 families while they find a place of their own. It would be an addition to their current facility near JFK Park.A recent Homeless Alliance of WNY study found almost half of those experiencing homelessness in Eri…