Changelog :

- changing location of main search engine from connector to web_client (connector engines should be more general, in case we also attach a local database search for local use if the general server is unreachable or down)
- adding action specific methods (list, create, retrieve, update, destroy)
- finishing file parsing and polishing to make it robust
- adding a Request class manager, that chains requests in case of pagination, automatically.
- adding pandas formatting to the connector core (not web_client)