[buganizer] Migrate DIR_METADATA for tools/

Migrate all metadata files for tools/ and mixins
used by metadata files under tools/.

Verify components with http://b/components/{id} or at
go/chrome-on-buganizer-prod-components.

Bug: chromium:1518875
Change-Id: I6e7c91aa64e69718dddb89f2f181eb68ef634b60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5264419
Commit-Queue: Jeff Yoon <jeffyoon@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/main@{#1259540}
NOKEYCHECK=True
GitOrigin-RevId: 1a023936e9f2e78eabcb0a32e5af7b8fba40471c
diff --git a/DIR_METADATA b/DIR_METADATA
index 03fa4c2..24ff85f 100644
--- a/DIR_METADATA
+++ b/DIR_METADATA
@@ -1,11 +1,6 @@
-# Metadata information for this directory.
-#
-# For more information on DIR_METADATA files, see:
-#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/README.md
-#
-# For the schema of this file, see Metadata message:
-#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/proto/dir_metadata.proto
-
-monorail {
+monorail: {
   component: "Tools"
-}
\ No newline at end of file
+}
+buganizer_public: {
+  component_id: 1456784
+}