added a bunch of missing Windows resource files and fixed a few minor bugs

**/Makefile.kmk: Cosmetic changes.

*.kmk: install path adjustments.

compile fixes if VBOX_WITH_MAIN is not defined

VBoxAuth for Linux / Solaris only if VBOX_WITH_PAM is enabled (default)

VRDPAuth -> VBoxAuth.

Updated VBox authentication library interface, removed references to VRDP.

generalized and moved auth modules