Trim the package cache by default, and split it from orphan removal

CleanCache was off, so nothing ever pruned /var/cache/pacman/pkg - 23 GB on the
machine this was found on, with three 3.2 GB copies of one package. Trimming
only drops older versions of installed packages and cached versions of
uninstalled ones, so the cost is downgrade depth, not working software.

flatpak uninstall --unused moves from CleanCache to RemoveOrphans, where it
belongs: unused runtimes are the Flatpak equivalent of orphaned packages, and
removing installed software should not hide behind a flag named for cache
trimming. RemoveOrphans stays off - 'orphaned' only means nothing depends on
it, which is also true of something installed deliberately.

The log now reports what a trim reclaimed, since a real paccache run says
almost nothing and there was otherwise no way to tell it was working.

src/lib/config.sh

@@ -96,7 +96,7 @@ cau_config_load() {
 	CFG_APPIMAGE=no;              cau_config_bool UpdateAppImages      yes && CFG_APPIMAGE=yes
 	CFG_DEVEL=no;                 cau_config_bool UpdateDevel          no  && CFG_DEVEL=yes
 	CFG_RESOLVE_CONFLICTS=no;     cau_config_bool AutoResolveConflicts yes && CFG_RESOLVE_CONFLICTS=yes
-	CFG_CLEAN_CACHE=no;           cau_config_bool CleanCache           no  && CFG_CLEAN_CACHE=yes
+	CFG_CLEAN_CACHE=no;           cau_config_bool CleanCache           yes && CFG_CLEAN_CACHE=yes
 	CFG_REMOVE_ORPHANS=no;        cau_config_bool RemoveOrphans        no  && CFG_REMOVE_ORPHANS=yes
 	CFG_NOTIFY_SUCCESS=no;        cau_config_bool NotifyOnSuccess      yes && CFG_NOTIFY_SUCCESS=yes
 	CFG_NOTIFY_ERROR=no;          cau_config_bool NotifyOnError        yes && CFG_NOTIFY_ERROR=yes