Allow attachment number to be included on file export
Configuration allows to setup different file name formats. It would be helpful to add "%n" placeholder (or similar) in the file format fields allowing include number of the attachment in the message. This would allow to keep similar format of exported attachment files as used on mojedatovaschranka.cz. Also, sometimes the order of files may have some meaning :-( e.g.: %i_%n_%f, resulting in export like: 435942427_0_Dopis.pdf, 435942427_1_Priloha.pdf,...