Adding support for reading out hardware version

[ryan-summers]

This PR fixes #144 by reporting the hardware revision in the service USB command.

I also moved delay to hardware since it's not used by the application anymore.

> service
Version             : v0.2.0-134-g9d6b5e0 [release]
Hardware Revision   : v1.5
Build Time          : Thu, 03 Feb 2022 12:57:55 +0000
Rustc Version       : rustc 1.57.0 (f1edd0429 2021-11-29)
Git revision        : 9d6b5e00876227413af993b609a8a5bd88dcd6b7 (dirty = true)
Features            : DEFAULT, PHY_W5500, W5500
Panic Info          : None
Watchdog Detected   : false