[FEATURE] Raw Json support

Is your feature request related to a problem?

Current JavaClient requires TypeMapping type which requires deserializing the Json Parser and Mapper to read raw json of mapping file using TypeMapping._DESERIALIZER. This process is not documented right now.

private String getAnomalyDetectorMappings() throws IOException {
        URL url = AnomalyDetectionIndices.class.getClassLoader().getResource(ANOMALY_DETECTORS_INDEX_MAPPING_FILE);
        return Resources.toString(url, Charsets.UTF_8);
    }

JsonpMapper mapper = sdkClient._transport().jsonpMapper();
        JsonParser parser = null;
        try {
            parser = mapper
                .jsonProvider()
                .createParser(new ByteArrayInputStream(getAnomalyDetectorMappings().getBytes(StandardCharsets.UTF_8)));
        } catch (Exception e) {
            e.printStackTrace();
        }

        CreateIndexRequest request = null;
        try {
            request = new CreateIndexRequest.Builder()
                .index(ANOMALY_DETECTORS_INDEX)
                .mappings(TypeMapping._DESERIALIZER.deserialize(parser, mapper))
                .build();
        } catch (Exception e) {
            e.printStackTrace();
        }

The mapper and parser should be present in java client and thus avoiding the user to create it on their end everytime.

What solution would you like?

When creating an index, provide a type to pass the raw json file directly which can be later parse on java client side to TyepMapping

request = new CreateIndexRequest.Builder()
                .index(ANOMALY_DETECTORS_INDEX)
                .mappingFile(<json_file_here>)
                .build();

What alternatives have you considered?

A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?

Add any other context or screenshots about the feature request here.

Start with java-client/src/main/java/org/opensearch/client/opensearch/indices/CreateIndexRequest.java and review how CreateIndexRequest.Builder currently accepts mappings. Read the TypeMapping._DESERIALIZER usage in the issue and determine how a mapping file should be passed and parsed by the Java client. Done means index creation can accept raw JSON mapping input without users creating the mapper and parser themselves.