Partials with multiple or named parameters

[mirko-incomedia]

This PR introduces support for multiple or named parameters in partials. The implementation follows the handlebarjs behavior and documentation: https://handlebarsjs.com/guide/partials.html#partial-parameters

[salesforce-cla[bot]]

Thanks for the contribution! Before we can merge this, we need @mirko-incomedia to sign the Salesforce Inc. Contributor License Agreement.

[theodorejb]

Partials with named parameters are supported in https://github.com/devtheorem/php-handlebars.