Add new palette backgrounds to options
Add new palette backgrounds to options

This fixes the name of the "Gray Background" to
"Blue Gray Background (Default)", and it adds the new backgrounds that
were added in ParaView MR !5287.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz