Update PEM channels ahead of ER12
Procedure: grab all new fast PEM channels being written to frame, within the PEM model, and add to channel list. Remove channels no longer being written to frame. (Any channels outside of the PEM model will need to be confirmed with Anamaria and/or Robert.)
Notes: From Duncan: L1:PEM-EX_ACC_ISCTEX_TRANS_Y_DQ was removed from L1_R frames See also Terra's Jan 2018 DetChar f2f talk: https://dcc.ligo.org/LIGO-G1800163