Add support for second-order tracking to CustomTransferMap

[Hespe]

Description

CustomTransferMap currently does only support linear tracking. This PR adds support for second-order CustomTransferMaps.

Motivation and Context

• I have raised an issue to propose this change (required for new features and bug fixes)
  • Closes Add support for second-order tracking to CustomTransferMap #516

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)

Checklist

• I have updated the changelog accordingly (required).
• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.
• I have reformatted the code and checked that formatting passes (required).
• I have have fixed all issues found by flake8 (required).
• I have ensured that all pytest tests pass (required).
• I have run pytest on a machine with a CUDA GPU and made sure all tests pass (required).
• I have checked that the documentation builds (required).

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[Hespe]

One thing that could lead to trouble down the road: predefined_transfer_map is interpreted differently based on how tracking_method is set. This should be fine during construction is potentially confusing if tracking_method is changed later, i.e. for the whole lattice at once.

An alternative would be to have two flags to set the tracking method. The current, public tracking_method to determine the tracking strategie used and a second private flag that determines how predefined_tracking_map is interpreted. Due to broadcasting, we cannot just check if predefined_transfer_map is three dimensional to distinguish these two modes.

So, essentially, I think changing tracking_method is confusing in the current implementation but its the most straightforward one. Maybe its worth to make it slightly more involved to prevent misleading tracking.