[BUG] Elasticsearch returner does not support v8+

Description

Starting with version 8, Elasticsearch removed document types. The
Elasticsearch returner requires the use of doc_type and (
despite spending over an hour digging through returner config loading) it's not
currently possible (at least without code changes) to turn that off.

Arguably, this could be considered a bug with how we load returner config
values. An example of what should work:

defaults = {'some': 'defaults', 'doc_type': 'default'}
config = defaults
config.update({'doc_type': None})

I couldn't figure out a reasonable way to do this without seriously modifying
the returner config loader.

Orthogonal to this issue is that we also can't use elasticsearch-py (pip
install elasticsearch) version 8, because one of the import statements no longer works with elasticsearch-py.

Read salt/returners/elasticsearch_return.py at the linked returner configuration and salt/modules/elasticsearch.py at the linked import. Reproduce the failures with Elasticsearch 8+ and elasticsearch-py 8, then determine the affected configuration and compatibility paths. Done means the Elasticsearch returner and module work with those versions without requiring document types.