Draft: support opensearch 2.x

[unautre]

Hello,

JanusGraph, as of right now, asks nicely the ElasticSearch instance about its version on graph opening. OpenSearch 1.x aimed to stay close to ElasticSearch 7.x, and says so in the default page:

$ curl -k http://localhost:9200/
{
  "name" : "1209e072b3e5",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "UZkz1kSfRFyfeUDaq211Mg",
  "version" : {
    "number" : "7.17.28",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "139cb5a961d8de68b8e02c45cc47f5289a3623af",
    "build_date" : "2025-02-20T09:05:31.349013687Z",
    "build_snapshot" : false,
    "lucene_version" : "8.11.3",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

OpenSearch, while mostly compatible with ElasticSearch, has different versions, and thus JanusGraph can't use it:

$ curl -k https://localhost:9200/ -u admin:admin
{
  "name" : "42a87b487a69",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "zguXGxbDQuO-s6FcuEy_Lw",
  "version" : {
    "distribution" : "opensearch",
    "number" : "1.0.0",
    "build_type" : "tar",
    "build_hash" : "34550c5b17124ddc59458ef774f6b43a086522e3",
    "build_date" : "2021-07-02T23:22:21.383695Z",
    "build_snapshot" : false,
    "lucene_version" : "8.8.2",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "The OpenSearch Project: https://opensearch.org/"
}

This pull request aims to fix that. It is still a Work In Progress, I intend to add unit tests to verify my changes soon(ish).