Scatter lowering

[rmoyard]

Description of the Change:

In the quantum dialect, I add a lowering for MHLO scatter to the MLIR tensor dialect. The reference for the implementation can be found here https://github.com/openxla/stablehlo/blob/main/docs/spec.md#scatter

Benefits:

This unlocks Jax array index with at and apply functions on it, for example:

    @qjit
    def add_multiply(l: jax.core.ShapedArray((3,), dtype=float), idx: int):
        res = l.at[idx].multiply(3)
        res2 = l.at[idx].add(2)
        return res + res2

    res = add_multiply(jnp.array([0, 1, 2]), 2)
    >>> [0, 2, 10]

Possible Drawbacks:

Some edge cases not properly covered.

[dime10]

We might want to wait until #216 is merged, since that PR is fairly heavy and close to being merged. It shouldn't be too much work to adapt this PR to the new compiler driver.

[dime10]

[sc-41325]

[erick-xanadu]

Still looking at it. Some small comments first.

[erick-xanadu]

Awesome! Great work @rmoyard!