Add OplusDoze app for pickup sensor handling

* Based off android_device_oneplus_oneplus3 doze app but
  with proximity related features stripped out and updated
  pickup sensor name.

Change-Id: I9f81b153948069cd4370c75817f12e91f6869e1d

doze/proguard.flags

@@ -0,0 +1,8 @@
+-keepclasseswithmembers class * {
+    public <init>(android.content.Context, android.util.AttributeSet);
+}
+
+-keep class ** extends android.support.v14.preference.PreferenceFragment
+-keep class org.lineageos.settings.doze.* {
+  *;
+}