Add initial CODEOWNERS file

(cherry picked from commit 50a6270e55e6d12a24031395943495120efd2d30)

docs/CODEOWNERS

@@ -0,0 +1,10 @@
+
+*               @elmindreda
+
+src/wl_*        @linkmauve
+
+docs/*.css      @glfw/webdev
+docs/*.less     @glfw/webdev
+docs/*.html     @glfw/webdev
+docs/*.xml      @glfw/webdev
+