Cache various ui color lookups in static LLUIColor

indra/newview/llfloatermodelpreview.cpp

indra/newview/llmanip.cpp

indra/newview/lloutfitgallery.cpp

indra/newview/llpanelobjectinventory.cpp

indra/newview/llpanelvoicedevicesettings.cpp

indra/newview/llsyswellitem.cpp

indra/newview/llsyswellwindow.cpp

indra/newview/lltoolbarview.cpp

indra/newview/llviewerchat.cpp

indra/newview/llviewertexteditor.cpp

indra/newview/llvoavatar.cpp