Intends to clarify how to make Embassy usable from within Visual Studio Code by assuming the presence of the Rust Analyzer.
Note that IntelliJ does not support the Rust Analyzer, so an open question remains as to the whether this is a good move. If it turns out not to be a good move then we should still look at clarifying the use of a workspace file.
One-shot mode now permits the sampling of differential pins, and the sampling of multiple pins simultaneously.
A new ChannelConfig structure has been introduced so that multiple channels can be configured individually. Further, the `sample` method now accepts a buffer into which samples are written.
Along the way, I've reset some default configuration to align with Nordic's settings in their nrfx saadc driver. Specifically, the channel gain defaults to 6 (from 4) and the time defaults to 10us (from 20us).
