Declare local FlowBlaze metadata in FlowBlaze loop

[daniele-moro]

FlowBlaze metadata is local to the FlowBlaze loop. There is no need to define them into the global metadata and can be kept local to the FlowBlaze loop (e.g., by defining a flowblaze_t flowblaze_metadata; at the beginning of the FlowBlaze loop). This will remove the need for adding the flowblaze_t into the user-defined metadata.