add support to elasticsearch/v9

[peczenyj]

The main intent of this PR is allow this internal improvement:

https://github.com/elastic/go-elasticsearch/blob/main/CHANGELOG.md#typed-api-1

This release introduces a new MethodAPI used by the TypedClient which makes the client friendlier for dead code elimination. Reducing the size of the client when only a subset of the APIs are used. The old API structure remains available for backward compatibility, but it is now deprecated.

to use it, we can just change the yaml tag and use the output elasticsearch_v9, should be backward compatible with the v8 tag

however, since we may keep elasticsearch v8 and v9 for a while, we may not benefit immediately from the dead code elimination but the main development today is on v9, it support earlier versions of go and I think we should consider add support on it.

since both codes are very similar, I did not try create like a "base" package to reuse the logic, but I can do if needed (or in another PR)

Regards