treewide: Add remote execution support

This adds support for remote execution by adding a target to build
a sandbox OCI image.

Change-Id: I848f705b7ea7311e20945ee8676cc7a52c8c33aa
Reviewed-on: https://review.monogon.dev/c/monogon/+/3783
Reviewed-by: Leopold Schabel <leo@monogon.tech>
Tested-by: Jenkins CI
diff --git a/build/platforms/BUILD.bazel b/build/platforms/BUILD.bazel
index a238039..217350a 100644
--- a/build/platforms/BUILD.bazel
+++ b/build/platforms/BUILD.bazel
@@ -29,3 +29,15 @@
     ],
     visibility = ["//visibility:public"],
 )
+
+platform(
+    name = "remote_amd64",
+    constraint_values = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+    exec_properties = {
+        "container-image": "docker://gcr.io/monogon-infra/sandbox",
+        "OSFamily": "linux",
+    },
+)