treewide: add aliases for third_party dependencies

With bzlmod it is currently not possible to access other third_party libraries. By adding an alias inside the root module we can work around this with a fairly moderate hack. We do have a folder and BUILD file for every dependency anyway, so this isn't that bad.

Change-Id: I472194f590fd4c4aa8ba304af70dd8b92ecc5c1e
Reviewed-on: https://review.monogon.dev/c/monogon/+/3231
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/third_party/BUILD.bazel b/third_party/BUILD.bazel
index 7d507bc..7df30fe 100644
--- a/third_party/BUILD.bazel
+++ b/third_party/BUILD.bazel
@@ -18,3 +18,10 @@
     },
     visibility = ["//visibility:public"],
 )
+
+# TODO: Workaround for https://github.com/bazelbuild/bazel/issues/19301
+alias(
+    name = "zlib",
+    actual = "@zlib",
+    visibility = ["//visibility:public"],
+)