Before this patch sysrescue-configuration.lua was executed twice each boot:
(1) during initramfs stage (2) in the regular system as sysrescue-configuration.service
While in theory both runs should create the same output, this isn't guaranteed and
differences could appear for example because of network issues. Finding and debugging
these is difficult because the output of sysrescue-configuration.lua created during
initramfs isn't available anymore when the final system is running.
This patch lets sysrescue-configuration.lua just run once during initramfs. The
output JSON file is then written to the new tmpfs mounted dir /run/archiso/config/.
This dir is also made the new default location for sysrescue-effective-config.json.
A symlink from /etc/sysrescue/sysrescue-effective-config.json to the new location
is created for compatibility with previous releases.
When you set a "sysrescuecfg" option on the boot command line before this change,
only the files given on the boot command line were read, not the files in the
sysrescue.d dir. But previous versions of sysrescue-configuration.lua had a set of
built-in default values, these were still used.
Current sysrescue-configuration.lua does not include default values anymore, they
are now all in 100-defaults.yaml. So it is better to always read the default values
from the sysrescue.d dir and just merge files given with the sysrescuecfg option
additionally, with a higher priority.
The sysrescuecfg now also allows absolute paths for local files. When using relative
paths, the common sysrescue.d dirs are prefixed. In this case the file will usually
be loaded again, but at a higher priority.
Previously when loading a YAML config, it overrode single values on the second hierarchy level.
But on all deeper levels new values were completely overwritten. This was inconsistent and poses
a problem for config entries that use these levels, like the ca-trust or the in-development autoterminal.
This change implements full merging of dictionaries on all levels to solve this. Values in files later
in precedence overwrite previous values. If the the old and the new config values are both dictionaries,
then the hierarchy levels are merged down recursively.
You can remove a previously existing dict entry again in a later file by assigning it an empty value.
Also fix handling of invalid YAMLs: ignore them instead of aborting execution
