Add helper functions extension

[thekid]

PHP:

use web\frontend\{Frontend, Handlebars};
use web\frontend\extension\Functions;

$frontend= new Frontend($handler, new Handlebars($this->environment->path('src/main/handlebars'), [
  new Functions([
    'top' => fn($node, $context, $options) => array_slice($options[1], 0, $options[0])
  ])
]);

Handlebars:

{{#each (top 3 comments)}}
  ...
{{/each}}

The parameters to these helper functions are the following:

• node: The current node, a com.github.mustache.Node instance
• context: The current context, a com.github.mustache.Context instance
• options: The resolved options passed, in the above example: [scalar(3), resolve(comments)]

[thekid]

Released in https://github.com/xp-forge/handlebars-templates/releases/tag/v1.1.0