Rejig the grid

[ferrisoxide]

Describe the task

The Scorecard grid is too slow to render, relying on complex SQL to build up the grid. We need to improve the speed dramatically if the app is to scale.

Success Criteria

• MUST render Transition Card grid in < 1 sec
• MUST render SDGs Card grid in < 1 sec
• SHOULD cache snapshots of historical grids for rapid presentation

Additional Notes

NB this may require implementing an event store model

Related Issues

• Background Job Server #961