Add `use-create` option to fail dups

[nik9000]

trafficstars

This adds an option to the bulk operation to force using Elasticsearch's create operation instead of index operation. We already were sending this operation when indexing into data streams. But this gives us the option when indexing into regular indices as well.

[nik9000]

I'm making this as draft without and tests or docs so folks can have a look and decide if its worth doing. I want this option enabled in the tsdb track so I can detect when I have a bad configuration. I used this to find the errors I fixed in https://github.com/elastic/rally-tracks/pull/251

[pquentin]

This is worth doing, yes!

[pquentin]

@elasticmachine update branch

[pquentin]

@nik9000 Are you still interested in working on this?