Fix issues with magic bytes sniffing

[marcospb19]

Did a refac for everything wrong with file signature sniffing.

• Fix sniffed file format overwriting input file
  • Fix asking Y/n question twice (consequence of the above)
• Remove extensions from output file path when sniffing made Ouch change the format used
• Fix Ouch not saying what format was sniffed so user decide to proceed
• Improve error message when sniffing fails
• Now halt if sniffing disagrees with extension format, sniffed format is likely the right one
  • Error message explains two ways to bypass