Save PDF as CODE_ID

[Julian-Theis]

PDF file should be saved as BOOKINGCODE_ROWID, i.e. ABCDE_15 where ABCDE is the booking code and 15 the unique row id of the patient. In this way, one can find labels after archiving a patient.

Furthermore, if the user does not close the PDF, but clicks again on print, one receives a permission denied error because the file is still open. This should be fixed, too.