Return Dataset[BinaryTile] so generated MVTs can be stored in a single output

[mojodna]

Overview

This is in addition to (optionally) writing individual MVTs out. This will save on object management and time taken to PUT individual tiles.

The single output contained generated MVTs can be subsequently processed to extract specific tiles or to write to an alternate data sink (e.g. MBTiles (#51)).

Checklist

• Add entry to CHANGELOG.md

[jpolchlo]

I approve of this concept. Would be good for benchmarking purposes as well to cut out the costly write operation. Would love to see if we can come up with a way to generate an MBTiles file out of one of these Dataset[BinaryTile] guys.

[jpolchlo]

Oh, but, we should hold off on deploying this until after 1.0.0

[jpolchlo]

This (I think) has been obviated by #140. Reopen if that's not true.

[mojodna]

👋 Not quite (as far as I can imagine). I can imagine using finalize to output a single file(set) per zoom, but returning Unit from the end of the pipeline makes it difficult (impossible?) to accumulate (ideally lazily and optionally) all of the tiles for all of the zooms into a single data frame (and potentially re-group tiles from multiple zooms together).