Show legends on graphs

[prawnsalad]

Is your feature request related to a problem? Please describe.
It is difficult to know what data actually means on a dashboard

Describe the solution you'd like
To show legends on graphs so that people know what they are looking at

Describe alternatives you've considered

Additional context
Looking at these graphs, you have no idea what each series is referencing.

Thank you for your feature request - we love each and every one!

[hgezim]

I want to add +1 to this.

One graph I got even shows same colors for 2 different lines:

[macobo]

cc @EDsCODE, cc #3338

How mixp@nel does this:

I think it makes sense to:

1. Show it outside the graph (either on the left or as a button on the graph)
2. Allow toggling values on-off

[paolodamico]

We now show legends on graphs!