port pixelated UA integration
legacy bitmask_client 0.9.2 shipped with integration of Pixelated UA, called Bitmask Mail. We need to port the bits that have changed now. The adaptors should be simpler this time since pixelated switched to use leap.bitmask.bonafide.
Some bits remain, however, that are still importing leap.mail. A pullreq should be sent to pix upstream to solve that.