[Feature request] One-liner summary

[AdityaKane2001]

Current state:
The current output shows all GPUs and all processes. This is informative, but is a bit verbose.

Proposed addition:
Have a one-liner to get state of all GPUs. It would contain the util % of all GPUs in a row (tab/2-space separated) in their respective colors.

Implementation details:
Add one more flag to the argparser (maybe "-ol", "--one-line"?), and get aggregate statistics from the output of parse_smi (maybe write a new function) and add a new function generate_line as a replacement for generate_table. Finally add the respective if-else block in main.

Let me know if this sounds feasible, if it does I'll create a PR for this.

/cc @alihassanijr