[core-server-kit] [feature] Fix our support for IPMI tools

[cuantar]

Modern servers all come with a BMC, a specialized ethernet interface that allows low-level hardware access (i.e. underneath the OS) via firmware. Our tools for dealing with IPMI are stale. This issue is a placeholder for revisiting them:

• sys-libs/freeipmi
• sys-apps/ipmiutil
• there's also ipmitool, but it's known to be buggy, despite its popularity

One of these is in better shape than the others and very easily builds, but I don't remember which. Another one has a dependency on nagios in the ebuild that maybe we want simply to remove. All of these things were documented in the Funtoo Jira bug tracker that disappeared after Funtoo's death, so will need to re-trace those steps and re-create the information here.