Update FindSIMD CMake

[zfergus]

Description

Update FindSIMD.cmake to now add support for Neon (Arm/Apple Silicon SIMD instruction set).

Credit: FindSIMD.cmake from Project CHRONO under BSD 3-Clause "New" or "Revised" License.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Compiles on M2 Mac.

Test Configuration:

• OS and version: macOS 13.5.2
• Compile and version: Apple clang version 14.0.3

Checklist:

• I have followed the project style guide
• My code follows the clang-format style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules