[QGIS-Developer] QEP: [Processing] Optional parameter groups

[Nyall Dawson]

Hi all,

Please see https://github.com/qgis/QGIS-Enhancement-Proposals/issues/120
for a new QEP regarding handling of optional parameter groups for
processing algorithms, designed to fix shortcomings in the GRASS
provider (and extend the possibilities for all algorithms).

If accepted, the changes will be backported to 3.0 to allow fixes to
GRASS algorithms in the 3.0 release.

Nyall