calculate eta and phi directly from AmgVector3d rather than TVector3

Before this MR:

• get TrigSiSpacePoint pointer to Trk::SpacePoint
• convert spacepoint.globalPosition() to TVector3
• use TVector3 eta and phi methods

After:

• get TrigSiSpacePoint pointer to Trk::SpacePoint
• use Amg::Vector3d eta and phi methods with spacepoint.globalPosition()

Since we have so many spacepoints there is a small improvement in timing.

I also changed the loop to range-based for.

Could be improved further by not shifting the spacepoints when retrieving from the SpacePointTool: maybe as a follow-up.