Adsk Contrib - Add support for ARM Neon intrinsics and Universal builds

[cedrik-fuoco-adsk]

This PR is about Add support for ARM Neon intrinsics #1753.

• Integrating sse2neon library to support ARM Neon intrinsic.
• Adding a new option to enable SIMD (DOCIO_USE_SIMD). OCIO_USE_SSE still works for now.
• Fixing issues that were preventing a universal build on MacOS.
• Universal build is now the default on MacOS.

Note that at least another commit will be needed once Adsk contrib - Add support for minimum and recommended versions for dependencies is merged into the main branch.

Some performance results with a MacBook M1 (using a custom heavy_transform.clf):

[cedrik-fuoco-adsk]

The branch is now rebased and conflicts have been resolved. The PR is ready to be reviewed. Could you take a look? Thanks in advance! @remia @doug-walker

[ConnorBaker]

Hi all,

I'd love to see these changes merged -- any remaining blockers?

Thank you for your work on this, @cedrik-fuoco-adsk!

[michdolan]

Closing since #1828 replaces this PR