2 - Download progress

[djalmaaraujo]

Implement download feature by calling the CLI to download the playlist.

Command to run:

python3 spotdl.py --playlist=https://open.spotify.com/user/spotify/playlist/37i9dQZF1DXc0iyNwZI144

• Get the output of this command and show a simple text like Downloading 23 of 78.
• Do a console.log() when it comes to and end
• Open a PR