feat: infiniband plugin

[spencermckee]

Description

Adds a plugin to collect metrics from the Nvidia Infiniband driver port counters at /sys/class/infiniband//ports//counters and debug status parameters at /sys/class/net//debug. The data is available as two new metrics, InfinibandCounterStats (labels: counter name, device, and port) and InfinibandStatusParams (labels: status param name and interface).

Checklist

• [x] I have read the contributing documentation.
• [x] I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• [x] I have correctly attributed the author(s) of the code.
• [x] I have tested the changes locally.
• [x] I have followed the project's style guidelines.
• [x] I have updated the documentation, if necessary.
• [x] I have added tests, if applicable.

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Please refer to the CONTRIBUTING.md file for more information on how to contribute to this project.