[x] consider the "mean time to transition" label, and make sure it makes sense
[ ] overall style review
[x] chart colouring for age of items charts
[x] chart colouring for workflow capacity chart
[x] Replace NVD3 legend with custom legend according to design (and align the "show as table" with them)
[ ] No need for date range - do we need to be clear that this is a "current date" report somehow?
[ ] Apply a retrospective date limit on the data considered (probably a year). This is needed for the capacity and the transition data, and probably the main query too