* Convert `SoftwareInterrupt` to a unit struct
* Remove the `SystemExt` trait and rename `SystemParts` to `SystemControl`
* Update all examples an HIL tests to reflect previous API changes
* Clean up imports in `hil-test` package, address `clippy` lint warnings
* Update `CHANGELOG.md`
* tests: Add clock_monitor HIL test
* feat: Adjust accepted freq ranges
* fix: Get the estimate a second time if its very off
* test: Update ranges and check