Move owners files into config/owners

The separate *_OWNERS files are related and can be grouped together
in a folder to make this distinction clear. This will allow us
to update the PRESUBMIT script to explicitly mark them as
exclusive change directory.

Note that the directory is named "owner", as we can't name it
"owners" as that is case-insensitive equivalent to "OWNERS",
which Windows can't handle in its presubmits.

DISABLE_THIRD_PARTY_CHECK=OWNERS update
R=yangguo@chromium.org

Bug: 1187573
Change-Id: Ib94a544c9dc01f788a8b75a5c8111ab52fbc27b8
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2814658
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Auto-Submit: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 6f5b44b..36a6ff0 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -39,7 +39,7 @@
 EXCLUSIVE_CHANGE_DIRECTORIES = [
     ['third_party', 'v8'],
     ['node_modules'],
-    ['OWNERS'],
+    ['OWNERS', 'config/owner'],
 ]
 
 AUTOROLL_ACCOUNT = "devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com"