move vector math out of libui

created a new header-only static libmath lib

Test: built & ran
Bug: n/a
Change-Id: Ic63ef5f54d9a0de07a9ab9e4d67be01ab6169fc0
diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index ea18644..d1bfa18 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -78,9 +78,13 @@
 
     static_libs: [
         "libarect",
+        "libmath",
     ],
 
-    export_static_lib_headers: ["libarect"],
+    export_static_lib_headers: [
+        "libarect",
+        "libmath",
+    ],
 }
 
 subdirs = ["tests"]