internals: setState api and efficient render updates

[toloudis]

Use Case

As a developer, the public api is too spread out over many functions that have partial side effects.
We would like to be able to update large chunks of state with only one function call.

Solution

Copy the data structure from https://github.com/allen-cell-animated/website-3d-cell-viewer/issues/110 down into volume-viewer and export it. Partially implement the react-like state update mechanism as discussed in Teams call in volume-viewer, starting only with VolumeOptions (our temporary name for the appearance and channel editing information). We believe this can be implemented at low technical risk as an alternate code path that doesn't modify any of the other public api or internal Drawable classes. After some nontrivial tbd amount of functionality is in, we can assess the impact on performance and code maintainability/readability.

The end goal which may require followup issues is to have all settings updated via this mechanism and remove the individual setters in the api. A requirement for the final goal will be to have good documentation of the whole data structure and a clear path forward for future modifications.

[toloudis]

@frasercl can you paste in the quick chunk of code you wrote so we have it here for reference?

[toloudis]

see #123 also, somewhat related

[frasercl]

Very closely related to #159, to the extent that it might be useful to attack both these issues together in a single refactoring effort