Adding support for first_event and first_response cursors in httpjson v2

[P1llus]

In the rewritten version of httpjson (v2), there is now cursor support, that is able to access last_event and last_response, so that it can use a chosen field as a cursor for the next requests (for example tracking the timestamp of the last event to filter on for the next interval).

However not all API's returns the newest event last, so we would need to accommodate for the API's that returns the newest event first.

2 Modules are currently blocked by this, Nessus and Cisco AMP.

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)