New Secruity namespace added

Move Passwords from Check to Security and deprecate old

Add new SymmetricEncryption and CreateKey

CreateKey class just creates keys for the SymmetricEncryption
SymmetricEncryption uses the hex2bin calls to convert the hex key to the
internal binary key

Example:
$key = CreateKey::generateRandomKey();
$encrypted = SymmetricEncryption::encrypt($string, $key);
$decrypted = SymmetricEncryption::decrypt($encrypted, $key);

Above $key must be stored in some secure location (.env file)

www/admin/class_test.php

@@ -81,6 +81,7 @@ print '<div><a href="class_test.mime.php">Class Test: MIME</a></div>';
 print '<div><a href="class_test.json.php">Class Test: JSON</a></div>';
 print '<div><a href="class_test.token.php">Class Test: FORM TOKEN</a></div>';
 print '<div><a href="class_test.password.php">Class Test: PASSWORD</a></div>';
+print '<div><a href="class_test.encryption.php">Class Test: ENCRYPTION</a></div>';
 print '<div><a href="class_test.math.php">Class Test: MATH</a></div>';
 print '<div><a href="class_test.html.php">Class Test: HTML/ELEMENTS</a></div>';
 print '<div><a href="class_test.email.php">Class Test: EMAIL</a></div>';