Configurable colors to rename line

Add to Konfigurator two options to set foreground and background colors to be
applied to the rename field.

FIXED: [ 301034 ] Rename input field doesn't respect text[NORMAL] when GTK theme is used
FIXED: [ 414968 ] Using provided custom colour package Midnight Commander, renaming files is difficult, as line colours are very pale.
BUG: 301034
BUG: 391996