Build: go back to ordering SUBDIRS by their usefulness

The dependency tracking still doesn't need any specific ordering to
build, but it's better to build DevTools and Libraries first so it
doesn't try to build two Applications that each need to wait for
libraries to be built, wasting a make child sitting around trying to
acquire the lock on the library directory.

Makefile

@@ -1,11 +1,13 @@
 SUBDIRS += \
  AK \
- Applications \
  DevTools \
- Kernel \
  Libraries \
+ Servers
+
+SUBDIRS += \
+ Applications \
+ Kernel \
  MenuApplets \
- Servers \
  Shell \
  Userland