Notes towards factoring out libraries/workflows

[tomalrussell]

• TC events/power system workflow - to its own repo as standalone?
• TC library: Track parsing; wind field model
• Optimised NetCDF calls
• fast geodesic calculations
• Mixed GADM levels boundaries layer workflow (e.g. ADM1 if available, fall back to ADM0)

Goals: reusable pieces at the right level of abstraction; more approachable to extend and maintain; opportunities to build on pieces without buying in to the whole framework.

Suggested approaches: make data products with workflows and publish the data (e.g. mixed GADM levels output); okay to have multiple small libraries if they're self-contained and do their thing well.