Soong package structure refactoring

Give prebuilt_etc and sh_binary their own packages and split the
gigantic main Android.bp up to small, per-package ones.

(This is a cherry-pick change.)

Test: m nothing, TreeHugger
Bug: 156980228
Change-Id: I7b00cd344b9f16861f1ff39edf0029f016b853d0
Merged-In: I7b00cd344b9f16861f1ff39edf0029f016b853d0
diff --git a/apex/Android.bp b/apex/Android.bp
new file mode 100644
index 0000000..144f441
--- /dev/null
+++ b/apex/Android.bp
@@ -0,0 +1,27 @@
+bootstrap_go_package {
+    name: "soong-apex",
+    pkgPath: "android/soong/apex",
+    deps: [
+        "blueprint",
+        "soong",
+        "soong-android",
+        "soong-cc",
+        "soong-java",
+        "soong-python",
+        "soong-sh",
+    ],
+    srcs: [
+        "androidmk.go",
+        "apex.go",
+        "apex_singleton.go",
+        "builder.go",
+        "key.go",
+        "prebuilt.go",
+        "vndk.go",
+    ],
+    testSrcs: [
+        "apex_test.go",
+        "vndk_test.go",
+    ],
+    pluginFor: ["soong_build"],
+}