Add credential management app preference to Settings

Background
* This is part of the work to support
  a credential management app on
  unmanaged devices.
Changes
* Add a preference controller which will only
  be enabled if there is a credential management app.
* Add a fragment to display details on the credential
  management app and its policy. Add a remove button
  to remove the credential management app.
* Link CredentialManagementAppAdapter to new fragment
  and add expander.

Manual Testing
* Verify preference is disabled if there is no credential
  management app.
* Verify preference summary shows credential mangement
  app name if a credential management app exists.
* Verify fragment details page displays the
  authentication policy correctly.

Bug: 165641221
Test: Manual testing
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.security.CredentialManagementAppFragmentTest
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.security.CredentialManagementAppControllerTest
Change-Id: I06d6b88d0c89022f7a6cbf3031834defcb54bd51

res/layout/app_authentication_item.xml

@@ -30,6 +30,7 @@
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_toRightOf="@id/app_icon"
+        android:layout_toLeftOf="@id/expand"
         android:layout_marginTop="16dp"
         android:layout_marginBottom="16dp"
         android:orientation="vertical">
@@ -40,6 +41,13 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"/>
 
+        <TextView
+            android:id="@+id/number_of_uris"
+            style="@style/AppAuthenticationPolicyNumberOfUrisText"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:visibility="gone"/>
+
         <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/uris"
             android:layout_width="wrap_content"
@@ -47,4 +55,11 @@
 
     </LinearLayout>
 
+    <ImageView
+        android:id="@+id/expand"
+        style="@style/AppAuthenticationExpander"
+        android:layout_width="30dp"
+        android:layout_height="30dp"
+        android:visibility="gone"/>
+
 </RelativeLayout>

res/layout/credential_management_app_policy.xml

@@ -0,0 +1,31 @@
+<!--
+  ~ Copyright (C) 2020 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:paddingBottom="5dip"
+    android:orientation="vertical">
+
+    <androidx.recyclerview.widget.RecyclerView
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:id="@+id/recycler_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:paddingTop="8dp"
+        android:scrollbars="vertical"/>
+
+</LinearLayout>