Add unpacking to update-util
Add unpacking to update-util

Description:
Add better command option handling
Use doc string for help message
Add formatting of help for docs
Add various options for listing/unpacking sections
Add option to unpack to 'staging directory' paths

Resolves: LE-5530
Change-Id: I1cc42e0b0ddf13668165876f21f955860c302fbd

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af