The Boston Theatre Conference, going on in the Hub this week, is partly a chance for the theater crowd to reassure each other that their medium is still relevant. But more importantly, it’s the first time that so many in the local scene have gathered to assess their position in Boston. “Noting that theater has often been the “stepchild” in the Boston arts scene, taking a back seat to such renowned institutions as the Boston Symphony Orchestra or the Museum of Fine Arts, [one moderator] asked the six panelists from a range of local companies to look at Boston’s current position in the theater world and to talk about how it might develop.”