pkg/utils: Preserve environment variables set by a KDE session

A KDE session sets some environment variables to influence the behaviour
of various programs and to access various settings [1].  eg., if the
KDE_SESSION_VERSION environment variable is absent then applications
won't respect KDE's theme or display scaling settings.

These environment variables are not meant to be set by the shell's
start-up scripts, but directly by KDE, and hence needs to be preserved
across the host operating system and Toolbx container.

[1] https://userbase.kde.org/KDE_System_Administration/Environment_Variables

containers#1696
containers#1698

Author: bkoropoff

src/pkg/utils/utils.go

@@ -93,6 +93,8 @@ var (
 		"HISTSIZE",
 		"HISTTIMEFORMAT",
 		"HOME",
+		"KDE_FULL_SESSION",
+		"KDE_SESSION_VERSION",
 		"KONSOLE_VERSION",
 		"LANG",
 		"SHELL",