Additional usage analysis

[joseph-palmer]

This PR adds more stats about each subscription's usage to the front end, including:

• The costs recovered per finance entry (along with percentage)
• Project and core spending totals, allowing us to see what spending links with what funding (project or core)
• Spending and allocation graphs with forecast (for current financial year).
• Expected spending (current financial year) based on forecast, including amount of new funds needed or left over.

Once working across all subscriptions, have a report page for Admin that shows the aggregated stats and forecasts to be used in an azure usage report.