Add Fullscreen in viewer, Track links with Google Analytics, Use .env file

- Fullscreen is a component that watches a store value set by the Carousel component on a picture click
- Use a .env file for API and website related settings and informations
- Google Analytics is now in place, tracking each routes link and viewer photo change

src/routes/_layout.svelte

@@ -71,9 +71,11 @@
         countries,
         locations
     } from '../utils/store'
+    import { stores } from '@sapper/app'
 
     // Components
     import Transition from '../utils/Transition'
+    import AnalyticsTracker from '../utils/AnalyticsTracker'
 
     // Props
     export const segment = null
@@ -96,7 +98,6 @@
     $locations.forEach(loc => loc.country = $countries.find(cont => cont.id === loc.country.id))
 </script>
 
-
 <style lang="scss" global>
     @import "../style/style.scss";
 </style>
@@ -104,3 +105,5 @@
 <slot></slot>
 
 <Transition />
+<AnalyticsTracker {stores} id={process.env.CONFIG.GA_TRACKER_ID} />
+