Add list timelines view

* get accounts list timelines from API
* display available lists in discover view tab
* display list timeline

mastodon/src/main/res/layout/item_list_timeline.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="64dp"
+    android:paddingLeft="16dp"
+    android:paddingRight="16dp"
+    android:paddingTop="12dp">
+
+    <TextView
+        android:id="@+id/title"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="@style/m3_title_large"
+        android:singleLine="true"
+        android:ellipsize="end"
+        tools:text="List"/>
+
+</RelativeLayout>

mastodon/src/main/res/values/ids.xml

@@ -12,6 +12,7 @@
 	<item name="discover_news" type="id"/>
 	<item name="discover_users" type="id"/>
 	<item name="discover_local_timeline" type="id"/>
+	<item name="discover_lists" type="id"/>
 
 	<item name="notifications_all" type="id"/>
 	<item name="notifications_mentions" type="id"/>

mastodon/src/main/res/values/strings.xml

@@ -387,4 +387,5 @@
 	<string name="privacy_policy_title">Mastodon and your privacy</string>
 	<string name="privacy_policy_subtitle">Although the Mastodon app does not collect any data, the server you sign up through may have a different policy. Take a minute to review and agree to the Mastodon app privacy policy and your server\'s privacy policy.</string>
 	<string name="i_agree">I Agree</string>
+    <string name="list_timelines">Lists</string>
 </resources>