Add more data on download_state_updated

In case of download start/stop/pause/complete/error an event download_state_updated is sent.
The event data are:

• gid: the gid of the download
• status: the status of the event active/paused/stoped/complete/error
• download.name: the name of the downloaded file
• download.total_length: the total length of the file (bytes)
• download.completed_length: the downloaded length of the file (bytes)
• download.download_speed: the current download speed (bytes / s)

theses data can be used on automation using template {{trigger.event.data}} followed by data name (example: {{trigger.event.data.download.name}})