KeyHandler: Integrate in tri-state-key handling via UEventObserver API

This basically adds required code to support both switch and extcon
based tri-state-key. This also adds tri-state-key-calibrate script for
devices that need to be calibrated on boot (OnePlus7+)

Change-Id: I2e6c5d2861569750bead05edacf6e328a5227077

KeyHandler/AndroidManifest.xml

@@ -17,6 +17,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           android:sharedUserId="android.uid.system"
           package="org.lineageos.settings.device">
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.VIBRATE" />
 
     <application
@@ -26,6 +27,15 @@
         android:defaultToDeviceProtectedStorage="true"
         android:directBootAware="true">
 
+        <receiver
+            android:name="org.lineageos.settings.device.BootCompletedReceiver"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="android.intent.action.LOCKED_BOOT_COMPLETED" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </receiver>
+
         <provider
             android:name=".ConfigPanelSearchIndexablesProvider"
             android:authorities="org.lineageos.settings.device"
@@ -49,6 +59,9 @@
             </intent-filter>
         </activity>
 
-        <activity android:name=".KeyHandler" />
-     </application>
+        <service
+            android:name=".KeyHandler"
+            android:permission="KeyHandlerService"
+            android:exported="false" />
+    </application>
 </manifest>