Embedded Types to Prevent Redundant Code

[cnguy]

It seems I can use this feature to clean up the code a lot.

A lot of the charts have similar properties & methods (WithTitle, With..., etc) and so this can be refactored to an embedded type.

Some examples of embedded types I could make are:
AggregatableChart which provides the ShowAverages ShowSums etc
BaseAxisChart which has height name values etc

[cnguy]

Due to the fact that there are no generics, I will switch from the builder-based API to the more common functional options-based API as described here.

Using this approach, the library will still have a type-safe and concise API with sensible defaults and a thin abstraction to allow more idiomatic Go code.

edit: In this codebase, it seems the varadiac configuration pattern will be better due to naming problems.

LineChartConfig vs BarChartConfig is a lot better than
LineChartTitle, BarChartTitle, LineChart etc

This design decision is still WIP >//<

[cnguy]

Frappe/charts is best represented with OOP and Go doesn't seem too good at that. Every approach I can think of has redundant code and so I think just leaving this library as it is right now is fine since the lib is tiny anyways.