fix: [feed-generator] Revert back the event initial search to use the…

… index endpoint instead of RestSearch

Relying on RestSearch was offering more flexibility than index in terms of filtering options,
however, it might introduce a significant overhead potentially leading to timeout.

examples/feed-generator/generate.py

@@ -62,7 +62,7 @@ def saveManifest(manifest):
 if __name__ == '__main__':
     misp = init()
     try:
-        events = misp.search(metadata=True, limit=entries, **filters, pythonify=True)
+        events = misp.search_index(minimal=True, limit=entries, **filters, pythonify=False)
     except Exception as e:
         print(e)
         sys.exit("Invalid response received from MISP.")