Adjust/update defaults for various parset parameters

This MR adjusts the default values of various parset parameters (see RAP-551). The following were changed:

• BDA is now off by default (it does not work properly with DD solution intervals)
• fast_datause = single for the fast solve and slow_datause = dual for the slow ones (support added in this MR)
• dd_interval_factor = 3 (DD solution intervals of up to 3 times the base interval)
• dd_psf_grid = [0, 0] (set to scale automatically with image size, resulting in ~ 1 PSF per square deg of imaged area)
• stepsigma = 2.0 (stops the solver earlier)
• solveralgorithm = directioniterative (required for both datause = single or dual and DD solution intervals)

Additionally, the behavior of apply_diagonal_solutions was changed to reflect the changes to WSClean (see https://wsclean.readthedocs.io/en/latest/facet_based_imaging.html#selecting-visibilities-to-read-reorder). When apply_diagonal_solutions is activated (the default), WSClean will now use the -diagonal-visibilities option when necessary and otherwise will use the -scalar-visibilities option. These options should reduce the I/O done during imaging significantly.