lint: remove unused resources

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

src/main/res/drawable/round_bgnd_icons.xml

@@ -1,24 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-    Nextcloud Android client application
-
-    @author Andy Scherzinger
-    Copyright (C) 2019 Andy Scherzinger
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-    GNU Affero General Public License for more details.
-
-    You should have received a copy of the GNU Affero General Public License
-    along with this program. If not, see <http://www.gnu.org/licenses/>.
--->
-<shape xmlns:android="http://schemas.android.com/apk/res/android"
-       android:shape="oval">
-    <solid android:color="#ffffff"/>
-</shape>

src/main/res/values/strings.xml

@@ -61,13 +61,11 @@
     <string name="prefs_value_theme_system">Follow system</string>
     <string name="prefs_theme_title">Theme</string>
 
-
     <string name="recommend_subject">Try %1$s on your device!</string>
     <string name="recommend_text">I want to invite you to use %1$s on your device.\nDownload here: %2$s</string>
     <string name="recommend_urls">%1$s or %2$s</string>
 
     <string name="auth_host_url">Server address https://…</string>
-    <string name="auth_username">Username</string>
     <string name="sync_string_files">Files</string>
     <string name="uploader_btn_upload_text">Upload</string>
     <string name="uploader_btn_alternative_text">Choose</string>