Convert LauncherPluginLib to soong

Bug: 148896221
Change-Id: I0c09ba2994cf2a8e230aebc51eb52a8acadf8686
diff --git a/Android.bp b/Android.bp
index cb695df..e132854 100644
--- a/Android.bp
+++ b/Android.bp
@@ -47,3 +47,14 @@
     },
     static_libs: ["libprotobuf-java-lite"],
 }
+
+java_library {
+    name: "LauncherPluginLib",
+
+    static_libs: ["PluginCoreLib"],
+
+    srcs: ["src_plugins/**/*.java"],
+
+    sdk_version: "current",
+    min_sdk_version: "28",
+}