Improve document extraction and including a document extraction command (#17183)

* Add extract documents content command

* Adding the extraction command and making the pure go pdf library as secondary option

* Improving the memory usage and docextractor interface

* Enable content extraction by default in all the instances

* Tiny improvement on archive indexing

* Adding App interface generation and the opentracing layer

* Fixing linter errors

* Addressing PR review comments

* Addressing PR review comments

store/sqlstore/file_info_store.go

@@ -350,19 +350,11 @@ func (fs SqlFileInfoStore) SetContent(fileId, content string) error {
 		return errors.Wrap(err, "file_info_tosql")
 	}
 
-	sqlResult, err := fs.GetMaster().Exec(queryString, args...)
+	_, err = fs.GetMaster().Exec(queryString, args...)
 	if err != nil {
 		return errors.Wrapf(err, "failed to update FileInfo content with id=%s", fileId)
 	}
 
-	count, err := sqlResult.RowsAffected()
-	if err != nil {
-		// RowsAffected should never fail with the MySQL or Postgres drivers
-		return errors.Wrap(err, "unable to retrieve rows affected")
-	} else if count == 0 {
-		// Could not attach the file to the post
-		return store.NewErrInvalidInput("FileInfo", "<id>", fmt.Sprintf("<%s>", fileId))
-	}
 	return nil
 }