po: Added missing files and sorted POTFILES

The new files are:

src/cm-unknown.c
src/cm-geldkarte.c
src/certchain.c
src/gpagenkeycardop.c
src/gpafileimportop.c
src/format-dn.c
src/keyimpseldlg.c
src/gpa-uid-list.c

• GnuPG-bug-id: T4214
• Signed-off-by: Werner Koch <wk@gnupg.org>