add fuel quantity to burner entities' info panel

[arl85]

I suppose this is more a suggestion than a bug report, so I'm posting here.

Furnaces show coal quantity in info panel, but this is not shown for burner driller and other burner-entities (like burner inserter).
My suggestion is to add this info to all burner entities' info panel

[Dark]

Supporting. This information in important in early game and very useful in end game for locomotives and cars.