Toward the end of the new film from writer and director Cristian Mungiu, “R.M.N.,” there is a riveting scene that takes place in a crowded auditorium. The entirety of a small Transylvanian village seems to be in attendance. The topic of conversation is the recent arrival of three men from Sri Lanka who’ve been hired by the town bakery. The locals resent their presence for reasons that are as narrow-minded as you might fear. Then other resentments arise, many of them long-standing. How long-standing? How about 700 years or so.