Adding MM Overlay to 21.3 (ATLASSIM-4065)
Adding MM overlay tools to 21.3
Also included is the RDO to Digit converters which are not currently used in MM overlay.
This MR is the 21.3 compatible version of the MM overlay in master !24616 (merged)
See (ATLASSIM-4066) and (ATLASSIM-4065).
This MR is the MM version of !MR26347