Raja Feather Kelly, an award-winning choreographer of recent Broadway musicals "A Strange Loop" and "Lempicka," as well as "Teeth," the recent Playwrights Horizons success imminently getting a commercial Off-Broadway run, makes his debut as a playwright with "The Fires," a work drenched in sorrow. The play examines three, actually four, Black men who inhabit the same third floor South Brooklyn railroad apartment in v…