Power down IO Masters

[nseidle]

This PR enables the user to easily turn off IO masters using SPI.end and Wire.end.

• Adds deinitialize() to Wire.end. This is the same function used in SPI.end.
• Change deinitialize to power down IO master, and only fire if handle is not NULL
• Add example showing how to successfully power down, then back up with more peripheral support.
• Update to HAL v2.4.1 on files apollo3.h, system_apollo3.h, and power control.

The changes are pretty minimal except for updating a few of the files to HAL 2.4.1. I needed it for power control but if it's too much, I can return to my original code that uses direct register writes (as Ambiq did in their earlier examples).

[oclyke]

Great step toward easy low-power configuration! I don't mind the partial update to 2.4.1