With elastic#30490 we have introduced a new way to provide request options
whenever sending a request using the high-level REST client. Before you
could provide headers as the last argument varargs of each API method,
now you can provide `RequestOptions` that in the future will allow to
provide more options which can be specified per request.

This commit deprecates all of the client methods that accept a `Header`
varargs argument in favour of new methods that accept `RequestOptions`
instead. For some API we don't even go through deprecation given that
they were not released since they were added, hence in that case we can
just move them to the new method.