Allow separate settings for omitting contacts from the dial by directory and the app's contacts list

Currently, when you omit a contact from the directory in the PBX settings, it omits them from both the dial by directory and the softphone contacts directory. It would be great to be able to have separate settings for each function. There are cases where we may want to omit a number from the dial by directory, but not the contacts list on the softphone or vice versa.