feat: add conversion logic from integer to english (#5540)

* feat: add conversion logic from integer to english

* feat: update DIRECTORY.md

* feat: fix linting issues

* feat: fix build issue

* feat: address review comments

---------

Co-authored-by: sailok.chinta <sailok.chinta@kotak.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>

src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java

@@ -0,0 +1,15 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class IntegerToEnglishTest {
+
+    @Test
+    public void testIntegerToEnglish() {
+        assertEquals("Two Billion One Hundred Forty Seven Million Four Hundred Eighty Three Thousand Six Hundred Forty Seven", IntegerToEnglish.integerToEnglishWords(2147483647));
+        assertEquals("One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven", IntegerToEnglish.integerToEnglishWords(1234567));
+        assertEquals("Twelve Thousand Three Hundred Forty Five", IntegerToEnglish.integerToEnglishWords(12345));
+    }
+}