secure_element: Update OWNERS

Remove all subtree OWNERS and add a root OWNER file
to simplify tracking

Test: NA
Change-Id: I08a6400eb03c42967773f02502a7501b4e258565
diff --git a/secure_element/OWNERS b/secure_element/OWNERS
new file mode 100644
index 0000000..492696b
--- /dev/null
+++ b/secure_element/OWNERS
@@ -0,0 +1,5 @@
+# Bug component: 456592
+alisher@google.com
+jackcwyu@google.com
+georgekgchang@google.com
+henrichataing@google.com