Feature: Escaping array dot notation

[iRedds]

Description
Sometimes an array key can contain a dot. In this case, you cannot access the value of this key using dot notation.
This PR makes available keys containing a dot, with dot notation.

$data = [
    'foo' => [
        'bar.baz' => 23
    ],
];

// Returns: 23
$barBaz = dot_array_search('foo.bar\.baz', $data);

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide