create components to aid in in-component arbitrary scale generation

[hamilton]

I often find that I sometimes want to create a specific internal scale that utilize the scale generation stuff we already have for DataGraphic. Making this easier will help unlock:

• easy custom small multiples
• in-plot grouping / faceting

This is probably going tor equire more than one component. I'd imagine

• OneDimensionalScale.svelte – allows user to embed a 1d scale anywhere. Would support type, domain, range, then output let:scale.
• TwoDimensionalScale.svelte – functionally the same as what DataGraphic.svelte natively offers today. Takes xType, yType, xDomain, yDomain, and I guess xRange, yRange. Provides slot props let:xScale and let:yScale.

An ideal end-state is probably this:

(1) scale generation functions in their own files, including logic to update scales based on parameters
(2) these two components built off of this functionality
(3) the TwoDimensionalScale.svelte component should probably be what determines the prevailing scales logic in DataGraphic.svelte