citrix_receiver: refactor so older versions can still be installed

Version 13.4.0 is the latest version that doesn't suffer from the bug
described at
https://discussions.citrix.com/topic/385459-ssl-error-with-135-works-with-134/page-2#entry1977735

As a result, upgrades to 13.5.0, 13.6.0 and 13.7.0 were postponed.
However some users aren't affected by this big. This enables everyone to
download the version that suits their needs.

Related to: #23975, #27664, #30029