chore(android): add AppConstants class

android/app/src/main/java/com/vernu/sms/AppConstants.java

@@ -0,0 +1,18 @@
+package com.vernu.sms;
+
+import android.Manifest;
+
+public class AppConstants {
+    public static final String API_BASE_URL = "https://api.textbee.dev/api/v1/";
+    public static final String[] requiredPermissions = new String[]{
+            Manifest.permission.SEND_SMS,
+            Manifest.permission.READ_SMS,
+            Manifest.permission.RECEIVE_SMS,
+            Manifest.permission.READ_PHONE_STATE
+    };
+    public static final String SHARED_PREFS_DEVICE_ID_KEY = "DEVICE_ID";
+    public static final String SHARED_PREFS_API_KEY_KEY = "API_KEY";
+    public static final String SHARED_PREFS_GATEWAY_ENABLED_KEY = "GATEWAY_ENABLED";
+
+    public static final String SHARED_PREFS_PREFERRED_SIM_KEY = "PREFERRED_SIM";
+}