[irqbalance] Add plugin for the IRQ balancing daemon

[suraj-cmd]

irqbalance is installed by default on Fedora, RHEL, Debian and Ubuntu, but sos
has no plugin for it and no other plugin references it. Its configuration never
reaches an sosreport, which matters when interrupts are not landing on the CPUs
an administrator expects.

The unit reads two environment files:

EnvironmentFile=@pkgconfdir@/irqbalance.env
EnvironmentFile=-@usrconfdir@/irqbalance

configure.ac resolves those to $prefix/etc/default and
${sysconfdir}/default, so the effective path differs between distributions.
Both conventional locations are collected, along with any systemd drop-ins,
since IRQBALANCE_BANNED_CPUS, IRQBALANCE_BANNED_CPULIST and
IRQBALANCE_ARGS are set there.

irqbalance.h defines the runtime socket directory as /run/irqbalance,
matching RuntimeDirectory=irqbalance/ in the unit; a listing of it is taken
rather than the sockets themselves.

The daemon holds no credentials, so no forbidden paths are needed.

Paths and the unit's environment file handling are taken from upstream
(misc/irqbalance.service.in, configure.ac, irqbalance.h) rather than a
running system. Confirmation of which of /etc/sysconfig/irqbalance and
/etc/default/irqbalance each distribution actually ships would be welcome —
I have collected both rather than guess.

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[packit-as-a-service]

Congratulations! One of the builds has completed. 🍾

You can install the built RPMs by following these steps:

• sudo dnf install -y 'dnf*-command(copr)'
• dnf copr enable packit/sosreport-sos-4425
• And now you can install the packages.

Please note that the RPMs should be used only in a testing environment.

[packit-as-a-service]

Congratulations! One of the builds has completed. 🍾

You can install the built RPMs by following these steps:

• sudo dnf install -y 'dnf*-command(copr)'
• dnf copr enable packit/sosreport-sos-4425
• And now you can install the packages.

Please note that the RPMs should be used only in a testing environment.