feat(configuration): allow to specify Elasticsearch index settings

[alexandrebouthinon]

What does this PR do ?

It add missing settings fields in the plugin configuration and make sure to use it during indices creation

How to test it?

Using the kuzzlerc file, you can now set the desired index settings. For example the following configuration:

{
  "plugins": {
    "device-manager": {
      "engineCollections": {
        "config": {
          "settings": {
            "number_of_shards": 3
          }
        },
        "asset": {
          "settings": {
            "number_of_shards": 4
          }
        },
        "assetGroup": {
          "settings": {
            "number_of_shards": 1
          }
        },
        "assetHistory": {
          "settings": {
            "number_of_shards": 3
          }
        },
        "device": {
          "settings": {
            "number_of_shards": 2
          }
        },
        "measures": {
          "settings": {
            "number_of_shards": 7
          }
        }
      }
    }
  }
}

gives you the following index configuration when you create a tenant:

Boyscout

Add a complete documentation about the plugin configuration usage

[rolljee]

Test are currently failing, but the rest looks good