Add ipmi_exporter to the prometheus exporters

[matanyall]

Request

I didn't see any discussion here before, but I would love to see IPMI monitoring support here in alloy! Most of the hard work is already done, as there is an ipmi_exporter already made that we can import here: https://github.com/prometheus-community/ipmi_exporter

Happy to take a crack at it as well, or work with someone on the implementation

Use case

I just want to monitor IPMI from my machines, and the remote IPMI interface at /ipmi in the exporter is interesting.