Merge KXMLGUI-files

• We don't really need separate rc-file for kpart, it's the same
• lineSeparator option does not seem to be doing anything
• Add "format_list_checkbox" action recently introduced to KPIMTextEdit
• Move "Delete" actions slightly lower to match the behavior of e.g. Dolphin

Tested both Kontact version and stand-alone application, seems to be fine