QOLOE-356 start of header split

[duttonw]

• Break apart the header into individual parts.
  • Handle the ability to have searchInput html or the searchData in the json passed to the searchInput partial
• Use the js/scss so storybook compiles directly for speed
• Have Handlebars init be called at the start for preview.js

header now calls these partials
handlebars.registerPartial("header_preMenu", header_preMenu);
handlebars.registerPartial("header_primary", header_primary);
handlebars.registerPartial("header_sitePreHeader_CTA_menuItem", header_sitePreHeader_CTA_menuItem);
handlebars.registerPartial("header_wrap", header_wrap);

todo:
loop the menu via the header_sitePreHeader_CTA_menuItem

tip: this.searchData == a way to use the root and only pass one element through.

{{#>header_wrap }}
  {{#>header_preMenu sitePreHeader=sitePreHeader siteHeader=siteHeader siteSearchAsset=siteSearchAsset dropdown_enabled=dropdown_enabled dropdown_options=dropdown_options siteSearchAsset=siteSearchAsset }}
  {{!put your own menu here }}
  {{/header_preMenu }}
  {{#>header_primary siteHeader=siteHeader }}
    {{#unless searchInput }}
      {{>searchInput  this.searchData }}
    {{else}}
    {{! search is fully overriden by html }}
      {{{ searchInput }}}
    {{/unless}}
  {{/header_primary }}
{{/header_wrap }}