pqProxyWidget: make showing group headers/footers optional

Make display of group headers and footers optional for custom
ParaView-based applications. Headers and footers are visible by
default, and are left on in the ParaView GUI application.
4 jobs for !4341 with enable-hide-property-group-headers
detached
Status Job ID Name Coverage
  Package
manual #5168749
linux docker paraview build manual
docs:generate
manual #5168748
linux docker paraview build manual
spack:centos7
 
  External
passed cdash-commit

failed ghostflow-branch-check-master