Package: move MODULES/SELECTOR to a different floppy

The IT build failed because the second 140K disk image got full.
This disk holds the "optional" DAs and the Selector (Shortcuts)
module. Shove that onto disk 3 instead.

No change for the 32MB and 800K packages.

Author: inexorabletash

bin/manifest

@@ -72,7 +72,7 @@ emit add_file $disposition "out/disk_copy.built" "Modules" "Disk.Copy" F10000
 
 # --------------------------------------------------
 # Part 3: Optional.
-disposition="optional"
+disposition="extra"
 
 # Add Selector
 emit add_file $disposition "out/selector.built" "Modules" "Selector" F10000