Updating ACTS seeding configuration for fast tracking

This MR includes changes to allow the configuration of the pixel seeding for fast tracking when using the ACTS workflow. At the moment, a selection is applied on the space points being used in the seeding tool. To be said, I am not very fun of the use of the hardcoded numbers in the implementation of the skipSpacePoint method, but I didn't want to define additional parameters in the algorithms. I have documented what the values are though. I am open for discussion on this point.

To properly configure the seeding tool additional changes on top of this MR are required when the ACTS version will be bumped.

FYI: @cvarni, @lfaldaul