Add layout for server button

rocket-chat-android-widgets/src/main/res/layout/server_button.xml

+<?xml version="1.0" encoding="utf-8"?>
+<com.facebook.drawee.view.SimpleDraweeView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:fresco="http://schemas.android.com/apk/res-auto"
+    style="@style/Base.Widget.AppCompat.Button.Borderless"
+    android:id="@+id/drawee_server_button"
+    android:layout_width="80dp"
+    android:layout_height="80dp"
+    fresco:actualImageScaleType="fitXY" />
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