basic data stream support for opensearch output plugin

### Use Case

The opensearch output plugin doesn't support data streams in opensearch yet. For metrics this is the preferred format in opensearch.

### Expected behavior

The elastic search plugin does already support it (see [this](https://github.com/influxdata/telegraf/pull/15613) PR). I suggest doing the same for opensearch, since it is a very simple change, which still enables using data streams with a predefined template.

Changes would be
- Adding a boolean config option that sets the bulkitem action to 'create' instead of 'index'.

Same limitations as the elastic plugin are in place, only works with 'manage_template' = false and 'overwrite_template' = false.

### Actual behavior

No support for data streams, currently get an error when using a predefined data streams template.

### Additional info

I already got it working locally, are you open for a PR for this functionality?

Start by comparing the OpenSearch output plugin with the Elasticsearch implementation and the referenced PR. Add the boolean option that switches the bulk item action from index to create, preserving the stated manage_template and overwrite_template limitations; done means predefined data streams can be used without the current error.

Written by the indexing model from the issue text.