add drag and drop builder

frontend/package.json

@@ -20,6 +20,7 @@
     "@angular/platform-browser": "^17.3.0",
     "@angular/platform-browser-dynamic": "^17.3.0",
     "@angular/router": "^17.3.0",
+    "leaflet": "^1.9.4",
     "rxjs": "~7.8.0",
     "tslib": "^2.3.0",
     "zone.js": "~0.14.3"
@@ -29,6 +30,7 @@
     "@angular/cli": "^17.3.17",
     "@angular/compiler-cli": "^17.3.0",
     "@types/jasmine": "~5.1.0",
+    "@types/leaflet": "^1.9.21",
     "autoprefixer": "^10.5.2",
     "jasmine-core": "~5.1.0",
     "karma": "~6.4.0",