…header constant names with Camel naming convention (apache#23442)

Renames the Exchange header string values in ElasticsearchConstants and
OpensearchConstants from non-Camel prefixed values (operation, indexId,
indexName, documentClass, waitForActiveShards, scrollKeepAliveMs,
useScroll, size, from, enableDocumentOnlyMode) to CamelElasticsearch* /
CamelOpensearch*, following the convention used across the rest of the
Camel component catalog and matching the pattern established in
CAMEL-23526 (camel-cxf), CAMEL-23522 (camel-mail), CAMEL-23461
(camel-aws-bedrock), CAMEL-23532 (camel-vertx-websocket /
camel-atmosphere-websocket / camel-iggy), and CAMEL-23576 (camel-jira).

The Java field names (PARAM_OPERATION, PARAM_INDEX_ID, PARAM_INDEX_NAME,
PARAM_DOCUMENT_CLASS, PARAM_WAIT_FOR_ACTIVE_SHARDS,
PARAM_SCROLL_KEEP_ALIVE_MS, PARAM_SCROLL, PARAM_SIZE, PARAM_FROM,
PARAM_DOCUMENT_MODE) are unchanged so routes referencing the constants
symbolically continue to work; routes using the literal string values
must be updated (documented in the 4.21 upgrade guide).

The already-Camel-prefixed PROPERTY_SCROLL_ES_QUERY_COUNT and
PROPERTY_SCROLL_OPENSEARCH_QUERY_COUNT constants are unchanged.

The generated Endpoint DSL header accessors on
ElasticsearchHeaderNameBuilder and OpensearchHeaderNameBuilder have been
renamed accordingly (operation() -> elasticsearchOperation() /
opensearchOperation(), indexId() -> elasticsearchIndexId() /
opensearchIndexId(), etc.).

All existing tests use symbolic constant references and continue to pass
without changes.

Tracker: CAMEL-23577

Reported by Claude Code on behalf of Andrea Cosentino

Signed-off-by: Andrea Cosentino <ancosen@gmail.com>