[ISSUE - 1167] Add support for child-first resolution

[sshailabh]

Handlebars.js uses child-first resolution instead of parent-first resolution: https://handlebarsjs.com/guide/expressions.html#changing-the-context

This pr allows to define the resolution(child-first vs parent-first) in the Handlebars intilaization allowing clients to decide the resolution method. Default resolution is parent-first making it backward compatible.

Issue link: https://github.com/jknack/handlebars.java/issues/1167

[DatApplePy]

@sshailabh That's awesome! Can't wait for it to be merged 🔥