Release notes draft for next version

Release vX.XX.XX

Bug Fixes:

Features:
 - Introduces management of 3rd-party repositories and content installed from them.
   A 3rd-party repository enables the distribution of user produced content. Multiple
   repositories can be managed along with the default upstream server. Most of the
   swupd subcommands used for managing upstream content are supported to manage
   3rd-party content along with most of their options.

Tests:
