This commit makes sure that mapping parameters to `CreateIndex` and
`PutIndexTemplate` are keyed by the type name.
`IndexCreationTask` expects mappings to be keyed by the type name.
It asserts this for template mappings but not for the mappings in the request.
The `CreateIndexRequest` and `RestCreateIndexAction` mostly make it sure
that the mapping is keyed by a type name, but not always.
When building the create-index request outside of the REST handler, there are
a few methods to set the mapping for the request. Some of them add the type
name some of them do not.
For example, `CreateIndexRequest#mapping(String type, Map<String, ?> source)`
adds the type name, but
`CreateIndexRequest#mapping(String type, XContentBuilder source)` does not.
This PR asserts the type name in the request mapping inside `IndexCreationTask`
and makes all `CreateIndexRequest#mapping` methods add the type name.
2cb172f079