Zabbix

........S. [ZBXNEXT-4002] add elasticsearch support as history storage

This implementation reuse the code alredy written for ZBXNEXT-3661,
in particular, the history processing code is the same as ZBXNEXT-3661.

The major changes required was the use of an NDJSON paylod for storing
data in batches in the zbx_history_add_values() function and changing
the zbx_history_get_values() function to use a POST request with a JSON
payload (as elasticsearch have a JSON-based DSL for performing searches).

The parsing of payloads in the zbx_history_get_values() functions was
modified for dealing with the elasticsearch format.

The use of the curl_multi_* api was retained as the code was already
working and also, if this will be promoted as our API for third party to
implement in an "history service", having parallelization capabilities is not
a bad idea.

Logging in the zbx_send_data() function can be improved. Actually it
report useful messages, but it can be a bit noisy if the storage is down.

Also the HistoryStorageTypes (former HistoryServiceTypes) parameter
was retained, as it was already implemented.