Add documentation for package scanner

[TheCakeIsNaOH]

trafficstars

The package scanner really needs to have its documentation page filled out: https://docs.chocolatey.org/en-us/community-repository/moderation/package-scanner

Here things I would like to see:

• What the size limit is for binaries, and how it shows up if a binary is too large.
• Information about how and why packages cannot be approved if the scanner has been exempted
• Information about how the scanner works with regards to what will break the scanning (number of scanned files doesn't match the number of expected files), how to write packages that don't break the scanner, and how it shows up as if the package has broken the scanner

[pauby]

@TheCakeIsNaOH There are still some internal discussion on where we want the scanner to go in future. Once that is agreed, then we can look to pick this up.