By Jeffrey Heller JERUSALEM (Reuters) -A sceptical president invited Prime Minister Benjamin Netanyahu on Tuesday to form a new government, after another inconclusive election deepened political stalemate in Israel. The country’s longest-serving leader, in power without interruption since 2009, now faces the tough challenge of enlisting enough allies for a governing coalition. Under law, Netanyahu will have 28 days to do so, with the possibility of a two-week extension before President Reuven Rivlin picks another candidate or asks parliament to choose one. Continued deadlock could ultimately r…