Move build/ to build/make/

Remove the nesting of build/{blueprint,kati,soong}, which should allow
us to use submodules.

Bug: 28001743
Test: Compare build-aosp_arm.ninja before/after
Change-Id: I5ff919cdb0423ebd11d9033fadab8aedf1a8b81d

default.xml

@@ -8,8 +8,14 @@
            remote="aosp"
            sync-j="4" />
 
-  <project path="build" name="platform/build" groups="pdk" >
+  <project path="build/make" name="platform/build" groups="pdk" >
     <copyfile src="core/root.mk" dest="Makefile" />
+    <linkfile src="CleanSpec.mk" dest="build/CleanSpec.mk" />
+    <linkfile src="buildspec.mk.default" dest="build/buildspec.mk.default" />
+    <linkfile src="core" dest="build/core" />
+    <linkfile src="envsetup.sh" dest="build/envsetup.sh" />
+    <linkfile src="target" dest="build/target" />
+    <linkfile src="tools" dest="build/tools" />
   </project>
   <project path="build/blueprint" name="platform/build/blueprint" groups="pdk,tradefed" />
   <project path="build/kati" name="platform/build/kati" groups="pdk,tradefed" />