Adds LockScreen SafetySource and SafetySource broadcast receivers.

Adds a basic LockScreen SafetySource with placeholder data.
Adds a no-op Biometric SafetySource.
Adds Broadcast Receiver and responds with data.

Test: atest SettingsUnitTests
Bug: 215516488
Bug: 215515448
Change-Id: I753a10f63fc73984c7ff96347b927bb2ca5a0aba

AndroidManifest.xml

@@ -4340,6 +4340,13 @@
                        android:value="true" />
         </activity>
 
+        <receiver android:name=".safetycenter.SafetySourceBroadcastReceiver"
+                  android:exported="true">
+            <intent-filter>
+                <action android:name="android.safetycenter.action.REFRESH_SAFETY_SOURCES"/>
+            </intent-filter>
+        </receiver>
+
         <!-- This is the longest AndroidManifest.xml ever. -->
     </application>
 </manifest>