feat(auditlog): ExecutionId on site SQLite schema + gRPC AuditEventDto

src/ScadaLink.Communication/Protos/sitestream.proto

@@ -91,6 +91,7 @@ message AuditEventDto {
   string response_summary = 17;
   bool payload_truncated = 18;
   string extra = 19;
+  string execution_id = 20;       // empty string represents null
 }
 
 message AuditEventBatch { repeated AuditEventDto events = 1; }