some cleanup
qpwstore:
  fix build
  show date of last modification
  provide open last used shortcut
  fix arg bug
  catch sigint in qpwstore
  use qt home dir functionality

detect if in ssh session

integrate authenticity and integrity in cli
fix windows build
remove unused c-bindings
remove unused interactive add
implement file input possibility for add command.
implement pwstore merge
simplify db backend: use data_type instead of custom tuple.
don't create backups of empty files
cleanup
update deps