DTS peripheral driver could be more user friendly

Currently, the DTS (Digital Temperature Sensors) driver returns the raw register value, which is the number of clock cycles needed to measure the frequency.

There is an example that shows how to use the DTS driver: https://github.com/embassy-rs/embassy/blob/main/examples/stm32h5/src/bin/dts.rs

I feel like a lot of that code should be inside of embassy-stm32.