Revamp support for building third-party apps via maven

- Publish onos-dependencies (autogenerated from deps.json). With most
  3rd-party dependencies listed as <dependencyManagement> to avoid
  version conflicts, and a minimal set listed as <dependencies> to
  simplify child poms. Similarly, we provide a number of plugins already
  configured as <pluginManagement> to support the whole life-cycle of
  apps (from build, to reporting and release).
- Update Maven plugins to work with JDK 11 (checkstyle, pmd, etc.)
- Publish onos-build-conf (with common checkstyle and pmd confs)
- Removed unused checkstyle code
- Fix OSGi version mismatch in deps.json to consistently depend on
  release 6 (the one supported by Karaf 4)
- Update/simplify archetypes to use onos-dependencies as the parent pom

Change-Id: Ic09b34e13fb49eb3d96df623b53a3617bbf7b7e4
diff --git a/tools/build/bazel/BUILD b/tools/build/bazel/BUILD
index d819d63..26590a7 100644
--- a/tools/build/bazel/BUILD
+++ b/tools/build/bazel/BUILD
@@ -26,6 +26,13 @@
     visibility = ["//visibility:public"],
 )
 
+py_binary(
+    name = "dependencies_pom_generator",
+    srcs = ["dependencies_pom_generator.py"],
+    main = "dependencies_pom_generator.py",
+    visibility = ["//visibility:public"],
+)
+
 java_binary(
     name = "onos_yang_compiler",
     main_class = "org.onosproject.yang.compiler.main.YangCompilerMain",