Show a banner in the event of a service outage.

We will now determine if there has been a service outage and render a
banner at the top of the conversation list if we detect that there has
been one.

res/drawable/reminder_background_error.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:state_pressed="true" android:drawable="@color/core_red_highlight" />
+    <item android:state_focused="true" android:drawable="@color/core_red_highlight" />
+    <item android:drawable="@color/core_red" />
+</selector>

res/layout/profile_group_share_view.xml

@@ -5,7 +5,7 @@
         android:id="@+id/container"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:background="@drawable/reminder_background"
+        android:background="@drawable/reminder_background_normal"
         android:focusable="true"
         android:orientation="horizontal"
         tools:visibility="visible">

res/layout/reminder_header.xml

@@ -5,7 +5,7 @@
     android:id="@+id/container"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:background="@drawable/reminder_background"
+    android:background="@drawable/reminder_background_normal"
     android:focusable="true"
     android:nextFocusRight="@+id/cancel"
     android:orientation="horizontal"

res/layout/unverified_banner_view.xml

@@ -5,7 +5,7 @@
         android:id="@+id/container"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:background="@drawable/reminder_background"
+        android:background="@drawable/reminder_background_normal"
         android:focusable="true"
         android:nextFocusRight="@+id/cancel"
         android:orientation="horizontal"

res/values/colors.xml

@@ -58,4 +58,7 @@
     <color name="transparent">#00FFFFFF</color>
 
     <color name="MediaOverview_Media_selected_overlay">#88000000</color>
+
+    <color name="core_red">#f44336</color>
+    <color name="core_red_highlight">#ef5350</color>
 </resources>

res/values/strings.xml

@@ -1361,6 +1361,7 @@
     <string name="reminder_header_invite_text">Take your conversation with %1$s to the next level.</string>
     <string name="reminder_header_share_title">Invite your friends!</string>
     <string name="reminder_header_share_text">The more friends use Signal, the better it gets.</string>
+    <string name="reminder_header_service_outage_text">Signal is experiencing technical difficulties. We are working hard to restore service as quickly as possible.</string>
 
     <!-- media_preview -->
     <string name="media_preview__save_title">Save</string>