cmd: Add --base2 option to ps to show model sizes in KiB/MiB/GiB

[theasp]

Add --base2 option to ps to show model sizes in KiB/MiB/GiB. It also shows a decimal place, but I consider this a feature.

industrial:~/projects/ollama-src$ ollama ps
NAME                                     ID              SIZE     PROCESSOR         UNTIL
DEFAULT/mistral-small-2409-22b:latest    671ad04c21ce    26 GB    7%/93% CPU/GPU    Forever

industrial:~/projects/ollama-src$ ollama ps --base2
NAME                                     ID              SIZE        PROCESSOR         UNTIL
DEFAULT/mistral-small-2409-22b:latest    671ad04c21ce    24.4 GiB    7%/93% CPU/GPU    Forever