* Deprecate types in index API
- deprecate type-based constructors of IndexRequest
- update tests to use typeless IndexRequest constructors
- no yaml tests as they have been already added in #35790
Relates to #35190
Some features have been deprecated since `6.0` like the `_parent` field or the
ability to have multiple types per index. This allows to remove quite some
code, which in-turn will hopefully make it easier to proceed with the removal
of types.
The REST Client is split into 2 parts:
* Low level
* High level
The High level client has a main common section and the document delete API documentation as a start.