OpenSearch support (and deprecate Elasticsearch)

[lnielsen]

The new Python packages needed for OpenSearch integration are on their way:

• https://pypi.org/project/opensearch-py/
• https://github.com/opensearch-project/opensearch-dsl-py

Brain dump of tasks:

• Add a wrapper layer in Invenio-Search/Invenio-Indexer (hopefully they are API still compatible, and we can manage with just import magic)
• Add setup extras to all modules that depends on invenio-search (i.e. pip install Invenio-search[opensearch1])
• Add support in docker-services-cli for opensearch
• Add support in docker-compose in RDM, ILS, Framework.
• Add support in pytest-invenio - rename fixtures from es to search etc.
• Document the search upgrade process (every new version likely requires new client)

In addition, we likely need:

• Finish Index-Migrator to support migrating an index form Elasticsearch to OpenSearch.