By Michael Holden LONDON (Reuters) -Former British minister Sajid Javid delivered a withering attack on Boris Johnson’s leadership on Wednesday, telling him and his fellow lawmakers in their ruling Conservative Party that it was time for the prime minister to resign. Javid stepped down as health minister on Tuesday, the first of a flurry of resignations of ministers who said they had lost confidence in Johnson and that he was not fit to govern. Considered a possible contender to replace Johnson should he quit or be forced out, Javid listed a series of scandals that had embroiled the prime mini…