dcgm-exporter README docker instructions contains incorrect commands and information

[mbacchi]

The dcgm-exporter README.md has incorrect information about running dcgm-exporter in Docker. There are 2 major problems with these instructions which we would appreciate you fix.

1. In the Docker section, you indicate that we should create a counters csv file with specific fields that you suggest should be used. Unfortunately using that counters file with the most recent version of the dcgm-exporter docker image (3.3.5-3.4.1) causes a segmentation violation:

   time="2024-04-09T21:14:41Z" level=info msg="Initializing system entities of type: CPU"
   SIGSEGV: segmentation violation
   

   If I provide no counters.csv file to the docker command it works fine. (For example using no -v argument in the recommended command in your step 2 here.)

2. Again in your recommended docker run command, you suggest using -e DCGM_EXPORTER_INTERVAL=3 which tells dcgm-exporter to read GPU metrics every 3 milliseconds. This is apparently too fast, and causes high CPU usage, which I found out when I opened this issue in the dcgm-exporter repository. The default is -e DCGM_EXPORTER_INTERVAL=30000, which does not cause a high CPU usage problem on the system

These two issues cause the dcgm-exporter to be unusable due to your suggested commands and usage. Please fix this documentation.