Move SPI functions to WireHelper library, reducing binary size when working with multiple sensors

This branch removes the write8, read8, and similar methods to the [WireHelper](https://github.com/therealmitchconnors/WireHelper) library, which should significantly reduce binary size on projects using multiple sensors, as long as they all use the WireHelper library.  

Note: This pull request is not yet ready to merge, as the WireHelper library is still in pre-release.  @microbuilder asked that I create an issue that would help him to review this when he gets time.