(string utils) create string utils for start to group all function there

app/src/main/java/com/keylesspalace/tusky/util/StringUtils.java

@@ -0,0 +1,19 @@
+package com.keylesspalace.tusky.util;
+
+import java.util.Random;
+
+public class StringUtils {
+
+    public final static String carriageReturn = System.getProperty("line.separator");
+    final static String QUOTE = "\"";
+
+    public static String randomAlphanumericString(int count) {
+        char[] chars = new char[count];
+        Random random = new Random();
+        final String POSSIBLE_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        for (int i = 0; i < count; i++) {
+            chars[i] = POSSIBLE_CHARS.charAt(random.nextInt(POSSIBLE_CHARS.length()));
+        }
+        return new String(chars);
+    }
+}