Graph Titles and Info tooltips on Dashboard

[carver]

Add some basic graph necessities to everything on the Glados main dashboard:

• [x] Title
• [ ] Axis name
• [x] Tooltip giving more explanation of the purpose of the graph
• [x] ~Node's announced radius~ Hm, the tooltip shows the radius in the chart, not sure what else this could mean. 🤷‍♂
• [x] Colors that make sense (Network coverage colors should just be light/dark versions of the same color, and avoid confusion with existing client type colors)

[mrferris]

Heads up the tooltip stuff was merged here: https://github.com/ethereum/glados/pull/282