Build release tarballs in bazel and add make bazel-release rule

cluster/BUILD

@@ -1,5 +1,7 @@
 package(default_visibility = ["//visibility:public"])
 
+load("@bazel_tools//tools/build_defs/pkg:pkg.bzl", "pkg_tar")
+
 licenses(["notice"])
 
 filegroup(
@@ -14,6 +16,31 @@ filegroup(
     srcs = [
         ":package-srcs",
         "//cluster/addons:all-srcs",
+        "//cluster/gce:all-srcs",
+        "//cluster/saltbase:all-srcs",
     ],
     tags = ["automanaged"],
 )
+
+# All of the manifests that are expected to be in a "gci-trusty"
+# subdir of the manifests tarball.
+pkg_tar(
+    name = "_manifests-gci-trusty",
+    package_dir = "gci-trusty",
+    visibility = ["//visibility:private"],
+    deps = [
+        "//cluster/addons",
+        "//cluster/gce:gci-trusty-manifests",
+        "//cluster/saltbase:gci-trusty-salt-manifests",
+    ],
+)
+
+pkg_tar(
+    name = "manifests",
+    mode = "0644",
+    package_dir = "kubernetes",
+    deps = [
+        ":_manifests-gci-trusty",
+        "//cluster/saltbase:salt-manifests",
+    ],
+)