This commit includes the used sovler in the dnfjson reply. This
is mostly information (e.g. in service logs) but also useful in
tests to ensure that the expected solver was really run.
Note that this needs https://github.com/osbuild/images/pull/723
first.
This moves the dnf and dnf5 code into a new osbuild module called
solver. The dnf specific code is in dnf.py and dnf5 is in dnf5.py
At runtime the osbuild-depsolve-dnf script reads a config file from
/usr/lib/osbuild/solver.json and imports the selected solver. This
currently just contains a 'use_dnf5' bool but can be extended to support
other configuration options or depsolvers.
At build time a config file is selected from tools/solver-dnf.json or
tools/solver-dnf5.json and installed. Currently dnf5 is not installed,
it will be added when dnf5 5.2.1.0 becomes available in rawhide (Fedora
41).
The error messages have been normalized since the top level functions in
osbuild-depsolve-dnf do not know which version of dnf is being used.
