feat: mark some functions in bevy_math as const

[DaAlbrecht]

Objective

Mark simple functions as const in bevy_math https://github.com/bevyengine/bevy/issues/16124

Solution

• Make them const

Testing

cargo test -p bevy_math --all-features

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[DaAlbrecht]

Sadly most functions I saw can't be marked as const until floating point arithmetic is marked as const in the std.

I quickly searched in bevy_color and bevy_ui but this seemed already done.