Add progress option for showing progress only

[afbjorklund]

After hiding the INFO messages, enable some progress.

Starting "default"

READY.

Showing the requirements as a progress bar, using pb.

Closes #1311

[afbjorklund]

The first commit is from #1308, it messes up the progress bar to have both that and the log at the same time.

INFO[0105] [hostagent] Waiting for the essential requirement 1 of 5: "ssh" 
Waiting 1 / 8 [--->________________________]  "ssh" (essential 1/5)             INFO[0115] [hostagent] Waiting for the essential requirement 1 of 5: "ssh" 
Waiting 1 / 8 [--->________________________]  "ssh" (essential 1/5)             INFO[0132] [hostagent] Waiting for the essential requirement 1 of 5: "ssh" 
Waiting 1 / 8 [--->________________________]  "ssh" (essential 1/5)             INFO[0133] [hostagent] The essential requirement 1 of 5 is satisfied 
Waiting 1 / 8 [--->________________________]  "ssh" (essential 1/5)             
INFO[0133] [hostagent] Waiting for the essential requirement 2 of 5: "user session is ready for ssh" 
INFO[0133] [hostagent] The essential requirement 2 of 5 is satisfied 
Waiting 2 / 8 [------>_____________________]  "user session is ready for ssh" (essential 2/5)

[afbjorklund]

Fixed the width, when not keeping the output but cleaning the progress bar.

Haven't yet fully decided, which option is the best - there are pros and cons...