Replace expressions with `setFeatureState` for choropleth and linestring vector tile visualizations

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# Motivation

The data-join technique can be used in choropleth and linestring visualizations to join metadata to geometry in vector tiles over a unique identifier (or primary key). The data-join technique currently uses expressions to do the join, which is slow to execute when joining more than 10k or so features.

# New feature

Use map.setFeatureState() released in GL JS v0.46 to perform the data-join technique. map.setFeatureState() requires a unique integer `id` value to be included with the vector tile source. Here's an example - https://bl.ocks.org/ryanbaumann/733ba99c5ca1d9d15259081b395e4b00

# Issues

* Since setFeatureState supports `id` values only, vector tiles must be created with this `id` in them in order to use setFeatureState().
* `id` values only support integers, so there would need to be an intermediate `mapping` table to join data between string values and integer `id` values.
* The difference between expressions and setFeatureState() data-join techniques should be hidden from the end user of the visualization library.

Start by locating the current expression-based data-join implementation and reviewing the linked setFeatureState example. Work out how vector-tile integer ids and string-to-integer mapping would be handled for choropleth and linestring visualizations while hiding the implementation choice from users. Done means both visualization types use the state-based join without changing their public behavior.

Written by the indexing model from the issue text.