Generates SWU update packages for swupdate (Python 3)

 swugenerator is a command line tool to create and modify SWUpdate's
 SWU update files based on templates. openssl is used to sign the SWU.
 .
 Features that swugenerator supports:
  * replace occurrencies of variables found in the CONFIG file
  * add sha256 to each artifact
  * check if an artifact should be encrypted and encrypts it
  * sign sw-description with one of the methods accepted by SWUpdate