Support search_after to use if for getting documents after and before a given document

[fmassot]

The search_after feature is now available in Quickwit.

We can now use it to implement the log context feature of the explore view.

Code pointers:

• get log row context function in elasticsearch plugin
• makeLogContextDataRequest in elasticsearch plugin

[idrissneumann]

Here's a pull request: #23

Seems working fine:

And in the logs:

grafana-quickwit-datasource  | logger=plugin.quickwit-quickwit-datasource t=2023-11-22T14:00:50.030529999Z level=info msg="Executing multisearch" searchrequests="[map[query:map[bool:map[filter:map[range:map[timestamp:map[gte:2023-11-22T06:25:46Z lte:2023-11-22T13:25:46Z]]]]] search_after:[1.700659546e+12] size:50 sort:[map[timestamp:map[order:desc]]]]]"