add a CGI module applet

[PeterPawn]

• add another applet, which is able to read the needed parameters from a HTML form and executes 'decode_export' for an uploaded file
• may be used with any CGI-enabled HTTP server, but without any additional code (beside the HTML form), to decrypt an exported settings file
• for users, who haven't access to an own system, which is supported by this project

[PeterPawn]

idea discarded