Including FEX files in L1TopoSimulation

This MR only for moving the old code from 21.3 in the master. It is important to do this MR in order to keep update our working environment for future development and it is very important for people to find the information quickly in the future without having to browser through the list of comments.

There is no Jira ticket associated with this MR but initial discussion can be found in following: https://indico.cern.ch/event/851186/

The previous MR request in release 21.3 associated with this push is: !22414 (merged)

@asonay ,@cmorenom ,@orlando