Changes

Added zt2zm2zt-smoothing to remove noise in MPACE_B winds (#1161)

BIT_CHANGING

In order to remove noise in the wind fields in MPACE_B, we added some smoothing.

* Added `zt2zm2zt`-smoothing to `diagnose_upxp` calls in `advance_xm_wpxp`
* Added `zm2zt2zm`-smoothing to `wp2` and `em` vars fed into `wp3_term_pr_turb_rhs` in `advance_wp2_wp3`
* Changed C_wp2_splat to 0.00 in default tunable_parameters.in

Moving PosInf to clubb_model_settings.F90

Changing openacc to openmp migration repo to a fork with a change to switch the order of copyins and copies. This is to allow us to only copyin the pdf_params structure, but copy the internal arrays. When the copying of the internal arrays happens first, followed by the copyin of the structure, we overwrite the pointers to the internal arrays on the GPU version of the structure. Hence why we want the copyins to precede the copy statements.