feat: define region server related messages (#79)

* feat: define region server related messages

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* finalise

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* generate language code

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* add missing field

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* push region id down

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* remove type alias for region id and column id

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* define query request

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* remove old java file

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* remove go code

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

---------

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

go/greptime/v1/common.pb.go

@@ -674,6 +674,7 @@ func (x *FlightMetadata) GetAffectedRows() *AffectedRows {
 	return nil
 }
 
+// TODO: deprecate this, and use the `ColumnDef` in region_server.proto instead
 type ColumnDef struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache