[Feature] Encrypt Multiple Files to Single One

[Dentrax]

I think it would be nice if we had the chance to encrypted multiple files and merge into one file.

Extension (.ext) : Custom file extension that we have previously determined with argument
Argument (-m) : To we able to encrypt more than one file
Argument (-o) : If the -m argument is used, it is mandatory to determine output file

Example:

We have these files: test1.jpg, test2.png, test3.jpeg

To encrypt just only one: cryptogopher -e test1.jpg

To encrypt multiple files: cryptogopher -e -m test1.jpg test2.png test3.jpeg -o README.MD

To extract decrypted files: cryptogopher -d -m README.MD

P.S.: We could think about the decryption system for multiple files.

[Mr-1311]

It could be but I'm kinda busy nowadays. Maybe I can add it later. PR's are welcome btw :)