Implement image preseeding

This pulls in the infrastructure to build OCI bundles with Bazel and adds a loader to
load them into containerd at runtime.

Test Plan: New E2E test using a simple hello world Go image.

Bug: T793

X-Origin-Diff: phab/D585
GitOrigin-RevId: 3bc5e35a89a80a9683778ced72cc79e2d0b684ed
diff --git a/core/tests/e2e/preseedtest/BUILD.bazel b/core/tests/e2e/preseedtest/BUILD.bazel
new file mode 100644
index 0000000..9536846
--- /dev/null
+++ b/core/tests/e2e/preseedtest/BUILD.bazel
@@ -0,0 +1,16 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_docker//go:image.bzl", "go_image")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["main.go"],
+    importpath = "git.monogon.dev/source/nexantic.git/core/tests/e2e/preseedtest",
+    visibility = ["//visibility:private"],
+)
+
+go_image(
+    name = "preseedtest",
+    embed = [":go_default_library"],
+    pure = "on",
+    visibility = ["//visibility:public"],
+)
diff --git a/core/tests/e2e/preseedtest/main.go b/core/tests/e2e/preseedtest/main.go
new file mode 100644
index 0000000..ceb3898
--- /dev/null
+++ b/core/tests/e2e/preseedtest/main.go
@@ -0,0 +1,23 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello world from preseeded image")
+}