Refactor templates.json files to better match Swig template inheritance behavior

[fdelaneau]

The behavior should be more like the Swig templating inheritance where a declared bloc replaces the default values unless explicitly declared.

// Common rules applied by default to all pages
"*": {
    "routeNameAsFilenameEnabled": true,
    "http-metas": {
      "content-type": "text/html"
    },
    "stylesheets": [
        {
            // "media": "screen", // optional - default: all
            "url": "/css/public.css"
        }
    ],
    "javascriptsDeferEnabled": true,
    "javascripts": [
        "/js/vendor/modernizr-2.8.3.min.js",
        "/js/tooltip.js",
        "/handlers/main.js"
    ]
},

// Specific rules for one page or section : WITHOUT stylesheets inheritance
// The stylesheet page.css will replace public.css while the rest of the rules are inherited (routeNameAsFilenameEnabled, http-metas, javascriptsDeferEnabled , javascripts)
"exempleWithoutInheritance": {
    "stylesheets": [
      {
        "url": "/css/page.css"
      }
    ]
},

// Specific rules for one page or section : WITH stylesheets inheritance
// The page stylesheets will be public.css followed by other-pages.css 
// Reversing the declaration order will also reverse the order in the final html page
"exempleAvecHeritage": {
    "stylesheets": [
    {
        "parent": "*",
        "url": "/css/other-page.css"
      }
    ]
}