Move existing UWB API classes to UWB apex

Following instructions from go/mainline-java-lib to move the existing
UWB API classes to the new apex.

Bug: 194906542
Test: Compiles
Change-Id: I08801b418c7ba42c76952f5a80745cd0057ca329
diff --git a/StubLibraries.bp b/StubLibraries.bp
index 44c55c2..1904c1f 100644
--- a/StubLibraries.bp
+++ b/StubLibraries.bp
@@ -250,6 +250,7 @@
     "framework-sdkextensions.stubs",
     "framework-statsd.stubs",
     "framework-tethering.stubs",
+    "framework-uwb.stubs",
     "framework-wifi.stubs",
     "i18n.module.public.api.stubs",
 ]
@@ -269,6 +270,7 @@
     "framework-sdkextensions.stubs.system",
     "framework-statsd.stubs.system",
     "framework-tethering.stubs.system",
+    "framework-uwb.stubs.system",
     "framework-wifi.stubs.system",
     "i18n.module.public.api.stubs", // Only has public stubs
 ]