Embassy time driver for TIMG

Implement [`embassy_time::Driver`](https://github.com/embassy-rs/embassy/blob/4e61d83555c1693da025bc7c9c1c8ecf335b65f1/embassy-time/src/driver.rs#L81) trait for the TIMG peripheral inside the esp32, esp32s2 & esp32s3. This will not be implemented for the esp32c2 or esp32c3 due to the fact that each timer group only has one alarm timer.