Viewer: Finally fix Carousel navigation depending on URL

- Instead of detecting every case using popState event or whatnot, used a Sapper page stores subscribe to go to the current photo from the URL param (findIndex in photos)
- No page transition when navigating between photos in Viewer, but runs In and Out
- Also shortened dispatches to direct value over an object

src/utils/Transition.svelte

@@ -22,18 +22,28 @@
     */
     let scope
     let firstLoad = true
+    let previousPage = ''
+
+    // Check if viewer
+    const isExcluded = path => path.includes(['/viewer/'])
 
     // 1. Watch page change
     page.subscribe(page => {
-        // Run the loader animation (only after first load)
-        if (!firstLoad) {
-            animateIn(scope)
+        // Run transition if page is not excluded
+        if (!isExcluded(previousPage) || !isExcluded(page.path)) {
+            // Run the loader animation (only after first load)
+            if (!firstLoad) {
+                animateIn(scope)
+            }
+
+            // TODO: Figure out how to delay the page rendering a little bit before the end of the transition panel ending
+
+            // Set pageReady to false (?)
+            pageReady.set(false)
         }
 
-        // TODO: Figure out how to delay the page rendering a little bit before the end of the transition panel ending
-
-        // Set pageReady to false (?)
-        pageReady.set(false)
+        // Update page for viewer navigation checking
+        previousPage = page.path
     })
 
     // 2. Watch when loaded changes