Infilling time points

[znicholls]

Is your feature request related to a problem? Please describe.

At the moment there is no way to use Silicone to infill timepoints. Say I have a timeseries with data at 2010, 2020 and 2100, there is no way to use silicone to infill e.g. 2050 and 2075.

Describe the solution you'd like

Given its infilling scope, Silicone should be able to do this.

Describe alternatives you've considered

Use a new package or just apply linear interpolation. Given we've already defined the API, we can probably do better than these options.

Additional context

Add any other context or screenshots about the feature request here.