Log more information when invoking efibootmgr

[M4rtinK]

We had recently had a few cases reported to us at the Anaconda installer project with users trying to install recent fedora on ARM machines only for the installation failing when bootupd is invoking efibootmgr, with very little information being captured in the system Journal.

One such case is captured in https://bugzilla.redhat.com/show_bug.cgi?id=2333190 and the only relevant data captured in Journal looks like this:

01:21:35,981 WARNING org.fedoraproject.Anaconda.Modules.Payloads:INFO:program:Running in chroot '/mnt/sysroot'... bootupctl backend install --auto --write-uuid --update-firmware --device /dev/nvme0n1 /
01:21:36,265 WARNING org.fedoraproject.Anaconda.Modules.Payloads:INFO:program:Could not prepare Boot variable: Read-only file system
01:21:36,265 WARNING org.fedoraproject.Anaconda.Modules.Payloads:INFO:program:error: boot data installation failed: installing component EFI: Updating EFI firmware variables: Adding new EFI boot entry: Failed to invoke efibootmgr
01:21:36,265 WARNING org.fedoraproject.Anaconda.Modules.Payloads:DEBUG:program:Return code: 1

This does not really tell us what happened or even with which parameters efibootmgr was executed so we could try reproduce the issue.

To improve the situation I would have the following suggestions for a bootupd RFE:

• log the with which parameters efibootmgr is invoked in journal
• log stderr from efibootmgr to Journal
• optimally might as well log also stdout from efibootmgr to Journal, unless its horribly verbose

Thanks in advance & we can certainly help with testing once this is available. :)