ftguess - identify zip subformats

[decalage2]

See zip_ident from AssemblyLine:
https://github.com/CybercentreCanada/assemblyline-base/blob/3633a4e72bd742b41ca4ebfd0ca2384161582405/assemblyline/common/identify.py#L461
https://github.com/CybercentreCanada/assemblyline-base/blob/master/assemblyline/common/identify.py#L461