Lower ES deprecation warning level to debug

[rudolf]

In #120044 we introduced an elasticsearch.deprecation logger context that logs on info level if an Elasticsearch request from Kibana returns a warning header.

However, this can be confusing for users because they can't action these deprecations. It would be better to lower the log level to debug but then enable this logger by default on Cloud. Because the elasticsearch.deprecation logger also logs deprecations caused by user queries like from the console app it could cause a lot of log volume. So we should create two separate loggers: elasticsearch.deprecation.kibana and elasticsearch.deprecation.user

On cloud we would only enable debug logs for elasticsearch.deprecation.kibana by adding the following to the config template:

logging.loggers:
  - name: elasticsearch.deprecation.kibana
    level: all

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[rudolf]

Closed in #123660

Given the work done in #120043 I don't think it's necessary to enable debug logging on Cloud, we should rather catch deprecated API usage during our development cycle.