Cache any pre-computed steps

[ryscheng]

Describe the feature you'd like to request

This is going to take a bit more thought, but we might want to cache some pre-computation, to reduce the load on render.

As a naive strawman, we should check if we can run queries that group by date.
If not, should we pre-compute that?

Probably we want to wait on this till after
#59

Describe the solution you'd like

TBD

Describe alternatives you've considered

TBD

[ryscheng]

TimescaleDB does pre-compute, let's try that

[ryscheng]

Timescale continuous aggregates does this for us
#258