Development - Added a validator for base64 encoded data

```php
<?php
use \HylianShield\Validator\Encoding\Base64;

$validator = new Base64; // Identical to new Base64(Base64::VALIDATE_PADDING);
$test = base64_encode($simpleData);
$validator->validate($test); // true
// This fails, because the padding will be validated and this is invalid padding.
$validator->validate('1234=='); // false

$test = base64_encode($hugeBlob);
// Introduce a newline after each 76 characters for e-mails.
// @see http://tools.ietf.org/html/rfc4648#section-3.1
$test = implode("\r\n", str_split($test, 76));
$validator->validate($test); // false, because we do not allow for CRLF.

// Allowing for CRLF is not required by the RFC, but it is suggested by the RFC and
// there are fairly important implementations that lean on the existence of line feeds.
$validator = new Base64(Base64::VALIDATE_PADDING | Base64::ALLOW_CRLF);
$validator->validate($test); // true
```

@CyberSecutor