[DAR-2347][DAR-2768][Internal] Add option for isotropic transform on annotations

[shernshiou]

Problem

This PR is to facilitate the new import and export mask and polygon annotation for the future MED_2D_VIEWER release.
We are moving towards mm system at Darwin which means the import and export of mask and polygon have to be rescaled.

Solution

Legacy ON:

• Mask annotations: Imported with isotropic transformation
• Polygon annotations: Imported/exported using current calculations (no changes)

Legacy OFF:

• Mask annotations: Imported raw (no isotropic transformation)
• Polygon annotations: Imported by multiplying with x, y pixdims (polygon space to mm space)
• Polygon annotations: Exported by dividing with x, y pixdims (mm space to pixel space)

Changelog

• Introduce a new legacy flag that maintains the old import export nifty logic.
• Mask and polygon annotation for nifty will be rescaled during import and export.

[linear]

DAR-2347 Update darwin-py to accomodate the removal of isotropic transformation

[shernshiou]

Setting this aside awaiting further discussion with @JBWilkie

[JBWilkie]

Setting this aside awaiting further discussion with @JBWilkie

@shernshiou Since this piece of work is turning out to be a bit more complex than first anticipated, would you like me to review & test it now, or wait until we've progressed it a bit more?

[linear]

DAR-2768 [PY] Rescale polygon annotation for MED-2D_VIEWER

[JBWilkie]

Reviewed approach with Shern in a call