Parallelize Rust function apply_givens_rotation_in_place

[kevinsung]

This loop here:

ffsim/src/gates/orbital_rotation.rs

Line 45 in 1e55524

Zip::from(&slice1).and(&slice2).for_each(|&i, &j| {

A straightforward attempt doesn't pass the compiler due to the use of unsafe BLAS functions.