Improve the usability of array runtime config

[d-v-b]

Fixes #3667 and #3666 by updating the docs about the default write_empty_chunks value, and adds some API to Array and AsyncArray so that the doc update could be done properly (i.e., without using private API).

The new API on Array and AsyncArray is as follows:

• AsyncArray.config is public (it was private)
• Array.config is a new property that exposes ._async_array.config
• AsyncArray and Array both have a .with_config method that creates a new AsyncArray / Array with an updated config.

This means users can now easily check the runtime configuration of an array, and get a new array (pointing to the same data) with a different configuration if they want.

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing d-v-b:feat/with-config (5d1df75) with main (0e61449)}

Summary

✅ 48 untouched benchmarks
⏩ 6 skipped benchmarks¹

Footnotes

1. 6 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩