added Inspirer project to gallery, including thumbntail

public/content/content.json

 [
-    {
+  {
+    "item": {
+      "title": "INSPIRER areas of case-studies",
+      "project": "INSPIRER",
+      "author": {
+        "firstName": "Sven",
+        "lastName": "Schneider",
+        "hftURL": "https://www.hft-stuttgart.de/forschung/projekte/aktuell/inspirer"
+      },
+      "project_year_start": "2021",
+      "project_year_end": "2024",
+      "project_is_on_going": true,
+      "imageLink":"imgs/thumbnails/Inspirer_Testgebiete_thumbnail.jpg",
+      "keywords":["CityGML", "Urban Planning","Participation", "Point Clouds", "Augmented Reality" ],
+      "description_en":"The INSPIRER project aims to develop an AR App for mobile devices that lets a citizen participate interactively in the city planning process. In the background point clouds are generated by the mobile device and used to match existing point clouds in order to orient the user.",
+      "description_de":"Das INSPIRER Projekt hat zum Ziel, die Bürgerbeteiligung in Stadtplanungsprozessen auf moderne Art und Weise, mittels einer im Projekt entwickelten AR App, zu vereinfachen. Mit dem Smartphone aufgenommene Punktwolken weren im Hintergrund mit bestehenden registriert um die Orientierung des Nutzers zu gewährleisten. "
+    },
+    "refIndex": 5,
+    "links": {
+      "demo": "https://kartta.hel.fi/3d/heating/Apps/Helsinki/view.html",
+      "publication": "https://doi.org/10.3390/ijgi9100602"
+    }
+  },  
+  {
     "item": {
       "title": "Concept and Evaluation of heating demand prediction based on 3D city models and the Energy ADE – case study Helsinki",
       "project": "Master Thesis",