Signal MC request for RTA with VELO gap of 49mm and mu=1

Request from RTA with VELO gap of 49mm as will be used through 2023 and interim mu=1. Done through stage6 as at this moment it is not expected that larger number of requests would be needed. Request is created by taking stage6 file from analogous request at mu=3 and modified beam options file, bookkeeping condition and added options file for root basket size.

@gcorti, might be helpful if you can check that I did not make any mistake. @cmarinbe, please check event types and number of events. Sample for minimum bias will come in separate MR.