feat(bazel): change ng_package rule to APF v6 (#22782)

Angular Package Format v6 stops bundling files in the esm5 and esm2015
directories, now that Webpack 4 can tree-shake per-file.

Adds some missing files like package.json to make packages closer to
what we publish today.

Refactor ng_package to be a type of npm_package and re-use the packaging
action from that rule.

PR Close #22782

packages/common/BUILD.bazel

@@ -19,7 +19,12 @@ ng_module(
 
 ng_package(
     name = "npm_package",
-    srcs = ["package.json"],
+    srcs = [
+        "package.json",
+        "//packages/common/http:package.json",
+        "//packages/common/http/testing:package.json",
+        "//packages/common/testing:package.json",
+    ],
     entry_point = "packages/common/index.js",
     secondary_entry_points = [
         "testing",

packages/common/http/BUILD.bazel

@@ -1,5 +1,7 @@
 package(default_visibility = ["//visibility:public"])
 
+exports_files(["package.json"])
+
 load("//tools:defaults.bzl", "ng_module")
 
 ng_module(

packages/common/http/testing/BUILD.bazel

@@ -1,5 +1,7 @@
 package(default_visibility = ["//visibility:public"])
 
+exports_files(["package.json"])
+
 load("//tools:defaults.bzl", "ng_module")
 
 ng_module(

packages/common/testing/BUILD.bazel

@@ -1,5 +1,7 @@
 package(default_visibility = ["//visibility:public"])
 
+exports_files(["package.json"])
+
 load("//tools:defaults.bzl", "ng_module")
 
 ng_module(