Migrate protobuf and protobuf-codegen to monorepo.

Bug: http://b/339424309
Test: treehugger
Change-Id: I4366278ea248f166f1b4580339b10d759e9cf52c

Android.bp

diff --git a/Android.bp b/Android.bp
index f51b33a..96beb97 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,74 +1 @@
-// This file is generated by cargo_embargo.
-// Do not modify this file because the changes will be overridden on upgrade.
-
-package {
-    default_applicable_licenses: ["external_rust_crates_protobuf-codegen_license"],
-    default_team: "trendy_team_android_rust",
-}
-
-license {
-    name: "external_rust_crates_protobuf-codegen_license",
-    visibility: [":__subpackages__"],
-    license_kinds: ["SPDX-license-identifier-MIT"],
-    license_text: ["LICENSE"],
-}
-
-rust_library_host {
-    name: "libprotobuf_codegen",
-    crate_name: "protobuf_codegen",
-    cargo_env_compat: true,
-    cargo_pkg_version: "3.2.0",
-    crate_root: "src/lib.rs",
-    edition: "2021",
-    rustlibs: [
-        "libanyhow",
-        "libonce_cell",
-        "libprotobuf",
-        "libprotobuf_parse",
-        "libregex",
-        "libtempfile",
-        "libthiserror",
-    ],
-}
-
-rust_test_host {
-    name: "protobuf-codegen_test_src_lib",
-    crate_name: "protobuf_codegen",
-    cargo_env_compat: true,
-    cargo_pkg_version: "3.2.0",
-    crate_root: "src/lib.rs",
-    test_suites: ["general-tests"],
-    auto_gen_config: true,
-    test_options: {
-        unit_test: true,
-    },
-    edition: "2021",
-    rustlibs: [
-        "libanyhow",
-        "libonce_cell",
-        "libprotobuf",
-        "libprotobuf_parse",
-        "libregex",
-        "libtempfile",
-        "libthiserror",
-    ],
-}
-
-rust_binary_host {
-    name: "protoc-gen-rust",
-    crate_name: "protoc_gen_rust",
-    cargo_env_compat: true,
-    cargo_pkg_version: "3.2.0",
-    crate_root: "src/bin/protoc-gen-rust.rs",
-    edition: "2021",
-    rustlibs: [
-        "libanyhow",
-        "libonce_cell",
-        "libprotobuf",
-        "libprotobuf_codegen",
-        "libprotobuf_parse",
-        "libregex",
-        "libtempfile",
-        "libthiserror",
-    ],
-}
+// This crate has been migrated to external/rust/android-crates-io.

cargo_embargo.json

diff --git a/cargo_embargo.json b/cargo_embargo.json
deleted file mode 100644
index 545a831..0000000
--- a/cargo_embargo.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "package": {
-    "protobuf-codegen": {
-      "device_supported": false
-    }
-  },
-  "run_cargo": false,
-  "tests": true
-}