Clean up unused protobufs (opensearch-project#320)

* clean up unused protobuf messsages

Signed-off-by: xil <fridalu66@gmail.com>

* Add RegexpQuery

Signed-off-by: xil <fridalu66@gmail.com>

* Fix test

Signed-off-by: xil <fridalu66@gmail.com>

* remove StreamBulk

Signed-off-by: xil <fridalu66@gmail.com>

---------

Signed-off-by: xil <fridalu66@gmail.com>

Author: lucy66hw

CHANGELOG.md

@@ -12,7 +12,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Changed
 
 ### Removed
-
+- Removed unused messages ([#319](https://github.com/opensearch-project/opensearch-protobufs/pull/319))
 ### Fixed
 
 ### Security