Handle spaces in labels (#3679)

* Unquote label in flask routes
Encode label in Camera.jsx

* Don't use preprocessor

* Update nginx location for cacheable images

web/src/routes/Camera.jsx

@@ -133,8 +133,8 @@ export default function Camera({ camera }) {
               className="mb-4 mr-4"
               key={objectType}
               header={objectType}
-              href={`/events?camera=${camera}&label=${objectType}`}
-              media={<img src={`${apiHost}/api/${camera}/${objectType}/thumbnail.jpg`} />}
+              href={`/events?camera=${camera}&label=${encodeURIComponent(objectType)}`}
+              media={<img src={`${apiHost}/api/${camera}/${encodeURIComponent(objectType)}/thumbnail.jpg`} />}
             />
           ))}
         </div>