feat: update environment variables in docker-compose and .env.example

.env.example

@@ -1,2 +1,3 @@
+NUXT_SITE_URL=http://localhost:3000
 NUXT_PUBLIC_URL=http://localhost:3000
 NUXT_PUBLIC_API=http://localhost:5555

docker-compose.yml

@@ -2,12 +2,13 @@ services:
   visione-frontend:
     build:
       context: .
-#      args:
+      args:
-#        NUXT_SITE_URL: "http://localhost:3000"
+        NUXT_SITE_URL: ${NUXT_SITE_URL}
-#    ports:
+        NUXT_PUBLIC_URL: ${BUILD_NUXT_PUBLIC_URL}
-#      - "5999:80"
+        NUXT_PUBLIC_API: ${BUILD_NUXT_PUBLIC_API}
     environment:
-      NODE_ENV: production
+      NODE_ENV: ${NODE_ENV:-production}
-      NUXT_PUBLIC_URL: "http://localhost:3000"
+      NUXT_SITE_URL: ${NUXT_SITE_URL}
-      NUXT_PUBLIC_API: "http://localhost:5555"
+      NUXT_PUBLIC_URL: ${NUXT_PUBLIC_URL}
+      NUXT_PUBLIC_API: ${NUXT_PUBLIC_API}
     restart: always