setting up run 4 menu for Phase-II devs

Added Run 4 menus of versions Dev, Physics and MC (with the intention that Physics and MC are kept empty for now). Name chosen to be Dev_pp_run4_v1.py to avoid having to rename the menu closer to the Run4 start. If you have comments on the name, please let me know.

Mapped to Run 3 L1 menu and added one unit test (TriggerMenuMT_HLT_Dev_pp_run4_v1_HLTReprocessing_prescale_ctest). No test in TrigValidation added so far.

Following Frank's comment, I closed MR !56756 (closed) and opened this one for 22.0 to avoid merge conflicts with TMMT.

Tagging @ebrost, @khoo , @sshaw , @tamartin , @aranzazu, @fwinkl for info and commenting in case something doesn't look right.