Add SIMD Everywhere

[tytan652]

Description

Add SIMD Everywhere to obs-deps

Motivation and Context

Reduce in-tree vendored deps in OBS Studio repo.

How Has This Been Tested?

Types of changes

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

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[RytoEX]

Noted one minor issue.

[PatTheMav]

Seems fine.

[RytoEX]

LGTM

Note that this will cause a divergence in SIMDe header versions between Windows, macOS and the various Linux distros, as the latter are subject to whatever packages they have available. I suppose if packagers need a specific version, they can patch in whatever they need.