build: Move bazel/utils.bzl into api/bazel (#26858)

Move bazel/utils.bzl into api/bazel

The api/... subtree depends on utils.bzl, but it is stored in //bazel,
not //api/bazel.  When the api sub-tree is exported as
"data-plane-api", the resulting repository is not buildable.

This attempts to fix that by changing the canonical location of
utils.bzl and updating the references to it.

Signed-off-by: Ryan Anderson <ryan@michonline.com>

Mirrored from https://github.com/envoyproxy/envoy @ 35ef2c4eeac8e930e3c00e40baaea5271590db41

bazel/BUILD

@@ -1,5 +1,5 @@
 load("@io_bazel_rules_go//proto:compiler.bzl", "go_proto_compiler")
-load("//:utils.bzl", "json_data")
+load(":utils.bzl", "json_data")
 load(":repository_locations.bzl", "REPOSITORY_LOCATIONS_SPEC")
 load(":repository_locations_utils.bzl", "load_repository_locations_spec")
 load(
@@ -15,6 +15,7 @@ licenses(["notice"])  # Apache 2
 exports_files([
     "repository_locations.bzl",
     "repository_locations_utils.bzl",
+    "utils.bzl",
 ])
 
 go_proto_compiler(

bazel/utils.bzl

@@ -0,0 +1,18 @@
+load("@bazel_skylib//rules:write_file.bzl", "write_file")
+
+def json_data(
+        name,
+        data,
+        visibility = ["//visibility:public"],
+        **kwargs):
+    """Write a bazel object to a file
+
+    The provided `data` object should be json serializable.
+    """
+    write_file(
+        name = name,
+        out = "%s.json" % name,
+        content = json.encode(data).split("\n"),
+        visibility = visibility,
+        **kwargs
+    )