A Boston investor that plans to buy the idled Saddleback Mountain ski area in Rangeley has asked the owners of the resort’s 121 condominiums to donate $5,500 each to help revive it. Efforts by intended buyer Arctaris Impact Investors of Massachusetts to get condo owners and philanthropists to invest $5 million toward the property through donations to a nonprofit organization have raised eyebrows in the Rangeley community. However, the prospective owners and new management said community involvement is needed for so-called “impact investing” in economically distressed communities, as it can show government partners that the community is interested in the project.