fix: define 'app_name' in ':app' module for F-Droid

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

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~  This file is part of AndroidIDE.
+  ~
+  ~  AndroidIDE is free software: you can redistribute it and/or modify
+  ~  it under the terms of the GNU General Public License as published by
+  ~  the Free Software Foundation, either version 3 of the License, or
+  ~  (at your option) any later version.
+  ~
+  ~  AndroidIDE 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 General Public License for more details.
+  ~
+  ~  You should have received a copy of the GNU General Public License
+  ~   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+  -->
+
+<resources>
+  <!--  Required by F-Droid-->
+  <string name="app_name" translatable="false">AndroidIDE</string>
+</resources>