By Michael Holden and Kylie MacLellan LONDON (Reuters) -Four of Boris Johnson’s closest aides resigned on Thursday in a turbulent day for his government, as the British prime minister tried to reset his administration in the face of a series of scandals that have put his position in peril. Johnson’s premiership is facing a growing crisis in the wake of anger over a series of alcohol-fuelled parties held at his Downing Street office and residence during coronavirus lockdowns which followed other missteps. Angry lawmakers in his own Conservative Party, some of whom have already called for his re…