Porting SCT spacepoint formation code to master (ATLIDTRKCP-174)

Hello,

accordingly to what discussed this morning at the ID SW group meeting, I'm preparing a MR for discussing the changes to the SCT space point formation provided by @gavrilen. I would invite people to have a look at the changes: @sroe, @oda, @npetters, @goblirsc, @nstyles, @wlampl, @emoyse.

I have tested that these changes are not changing the output for both q431 and q221.

Cheers, Noemi