Change DevStack plugin to deploy OpenSearch 1.x instead of Elasticsearch
when using the elasticsearch storage driver. This is in preparation for
supporting OpenSearch instead of Elasticsearch. Note that CloudKitty
does not work with OpenSearch 2.x yet, likely due to the removal of
mapping types [1].

[1] https://opensearch.org/docs/2.0/breaking-changes/#remove-mapping-types-parameter

Change-Id: I572cba384a9a16ee2bbfe07b5c316ed5abbb5681
(cherry picked from commit 5fdb65b)

To facilitate the switch from Elasticsearch to OpenSearch, the ES
backend has been duplicated and renamed where appropriate to OpenSearch.

The OpenSearch implementation was modified in places for compatibility
with OpenSearch 2.x, for example:

- remove mapping name from bulk API URL
- replace put_mapping by post_mapping

This will allow for the future removal of the Elasticsearch backend.

Change-Id: I88b0a30f66af13dad1bd75cde412d2880b4ead30
Co-Authored-By: Pierre Riteau <[email protected]>
(cherry picked from commit 964c670)