Missing pressure control in buoyantSimpleFoam

Functionality to add/problem to solve

Add pressure control to buoyantSimpleFoam, to make it consistent with buoyantPimpleFoam and other compressible solvers.

Target audience

Anyone who experiences convergence issues with this solver, especially in the initial iterations.

Proposal

Implementation can be easily ported from other solvers.

Funding

I am attaching a patch with an implementation. ENH-add-pressure-control-to-buoyantSimpleFoam.patch