First release of aria2 integration

This integration allow to have information about aria2 server, and allow to manage downloads.

The following sensor are available:

• download_speed: the current global download speed or your aria2 server
• upload_speed: the current global upload speed or your aria2 server
• number_of_active_download: the total number of active download
• number_of_waiting_download: the total number of download waiting to start or resume
• number_of_stopped_download: the total number of downloaded file

The following services are available:

• aria2.start_download: allow to start a direct download. This service take url as parameter
• aria2.remove_download: remove a download. This service take the download gid as parameter.
• aria2.pause_download: remove a download. This service take the download gid as parameter.
• aria2.resume_download: remove a download. This service take the download gid as parameter.

The following events are available:

• download_state_updated: send when the state of a download is updated. The event contains two data:
  • gid: the download id
  • status: the status of the download. active/paused/stoped/complete/error

This integration can be used with aria2-card to display downloads on dashboard