We now have a new page /bills that shows any bills on the left-hand side (type, date, amount)
and bill types and some derived values (frequency and annual growth rate) on the right-hand side
The new bill, and new bill type buttons/logic all work
The delete bill and bill type buttons/logic all work
The change bill type logic all works (and is a touch complex, it alters the GUI
to show/hide different buttons, and disable/re-enable content in the bill types
table
THe change bill is disabled for now and for later
