ui/display and ui/display/util OWNERS update

This CL adds an OWNERS file to //ui/display/util:

git shortlog ui/display/util --numbered --summary
     5  Miguel Casas-Sanchez
     5  robert.bradford
     2  Daniel Bratell
     2  afakhry
     2  thomasanderson
[...]

I was going to add dnicoara@ to it but he seems more
a //ui/display OWNER:

git shortlog ui/display/ --numbered --summary
    51  kylechar
    31  dnicoara
    27  dnicoara@chromium.org
    21  robliao
    16  Christopher Cameron
    16  oshima

So I added him there. Also Component.

Bug: 821393
Change-Id: I695ac3948355783f19d0f31096f5ca8e37aa9eab
Reviewed-on: https://chromium-review.googlesource.com/960577Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Miguel Casas <mcasas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543103}

ui/display/OWNERS

+afakhry@chromium.org
 derat@chromium.org
+dnicoara@chromium.org
 marcheu@chromium.org
 oshima@chromium.org
-afakhry@chromium.org
+
+# COMPONENT: UI

ui/display/util/OWNERS

+dcastagna@chromium.org
+mcasas@chromium.org
+
+# COMPONENT: OS>Kernel>Graphics