Support for NVIDIA Jetson platforms

[jaywonchung]

NVML is not supported on Jetson platforms, e.g. Jetson Nano. Supporting Jetson platforms can be very useful for people who do ML/MLSys research on embedded platforms. Related discussion entry: https://github.com/ml-energy/zeus/discussions/102

We can make this a new zeus.device.

Things to figure out:

• [x] Get access to an actual Jetson device (Got access to Jetson Nano via cloud)
• [x] Try out the sysfs interface for power measurement.
  • INA3221 power monitor available via sysfs. CPU, GPU, and total. Likely not DRAM.
• [ ] Are there any control knobs on the platform, like power limit?
  • DVFS seems to be supported for the CPU and GPU, either via sysfs or the nvpmodel interface.

Energy measurement is now supported via #167 by @jxunn. See: https://ml.energy/zeus/measure/#jetson-platforms

[jaywonchung]

#167 for measurement support