Dynamic localization

[marian-ene-customsoft]

The changes would allow leveraging the {{ lang }} handlebar params to dynamically switch the current language on the BigCommerce StoreFront.

It would work verry well with a new handlebar for retrieving a query parameter as shown bellow
`'use strict';
const utils = require('handlebars-utils');
const common = require('./lib/common.js');

const factory = globals => {
return function(url, key) {
url = common.unwrapIfSafeString(globals.handlebars, url);
if (utils.isString(url)) {
const decodedURL = unescape(url);
const query = decodedURL.split('?');
if (query.length > 1) {
const params = new URLSearchParams(query[1]);
return params.get(key);
} else return 'en';
}
};
};

module.exports = [{
name: 'getURLQueryParam',
factory: factory,
}];`