feat: add support for FileInfo artifact source type

[gaelmuller]

Add support for a custom artifact source type FILE_INFO which can be used to collect information about the file without collecting its content:

• MD5
• SHA1
• SHA256
• Mimetype
• Basic PE Metadata, including imphash

[ant1]

There should be an example on how to use it, for instance in the examples directory add a file with:

name: System32 Metadata
doc: Metadata about dll and exe files in System32.
sources:
- type: FILE_INFO
  attributes:
    paths:
    - '%%environ_systemroot%%\System32\*.dll'
    - '%%environ_systemroot%%\System32\*.exe'
    - '%%environ_systemroot%%\System32\**\*.dll'
    - '%%environ_systemroot%%\System32\**\*.exe'
    separator: '\'
supported_os: [Windows]