Add DIR_METADATA files to //sandbox

Add Generate DIR_METADATA files and remove metatada from OWNERS files for //sandbox.

R=rsesek@chromium.org

Bug: 1113033
Change-Id: I2f065eb72e6f42f840ada0da5972c181c2f50265
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454255
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815356}

sandbox/DIR_METADATA

+# Metadata information for this directory.
+#
+# For more information on DIR_METADATA files, see:
+#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/README.md
+#
+# For the schema of this file, see Metadata message:
+#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/proto/dir_metadata.proto
+
+monorail {
+  component: "Internals>Sandbox"
+}
+team_email: "security-dev@chromium.org"
\ No newline at end of file

sandbox/OWNERS

@@ -4,6 +4,3 @@ palmer@chromium.org
 rsesek@chromium.org
 tsepez@chromium.org
 wfh@chromium.org
-
-# TEAM: security-dev@chromium.org
-# COMPONENT: Internals>Sandbox

sandbox/linux/OWNERS

@@ -2,6 +2,3 @@ jorgelo@chromium.org
 mpdenton@chromium.org
 palmer@chromium.org
 rsesek@chromium.org
-
-# TEAM: security-dev@chromium.org
-# COMPONENT: Internals>Sandbox

sandbox/mac/OWNERS

 kerrnel@chromium.org
 mark@chromium.org
 rsesek@chromium.org
-
-# TEAM: security-dev@chromium.org
-# COMPONENT: Internals>Sandbox

sandbox/policy/OWNERS

 set noparent
 file://sandbox/OWNERS
-# COMPONENT: Internals>Sandbox
-# TEAM: security-dev@chromium.org

sandbox/win/OWNERS

@@ -2,6 +2,3 @@ ajgo@chromium.org
 forshaw@chromium.org
 jschuh@chromium.org
 wfh@chromium.org
-
-# TEAM: security-dev@chromium.org
-# COMPONENT: Internals>Sandbox