cmds.distro: Move all modules to lib

Functions abstracting the distribution are not only needed in the
context of the distro subcommand, but also by other code, so make the
bulk of the code abstracting the distribution available in some place
more universally useful than below cmds.distro.

This commit leaves the source files mostly unchanged. They are only
patched to fix import paths, so that functionality is preserved.
Refactoring the code from command-line API to library API will be
done by the next commit.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/cmds/distro/Cmd.py

@@ -2,13 +2,15 @@
 
 import os, importlib
 
+from ...lib.log import *
+from ...lib.distros.Util import Util
+
 from ..Cmd import Cmd as Base
 from ..CmdDistro import CmdDistro
-from .backend.Util import Util
 
 class Cmd(Base): # export
 
-    from .backend.Backend import Backend
+    from ...lib.distros.Backend import Backend
 
     def __init__(self, parent: CmdDistro, name: str, help: str) -> None:
         super().__init__(parent, name, help)
@@ -35,16 +37,16 @@ class Cmd(Base): # export
                     backend_id = 'redhat'
                 case 'opensuse' | 'suse':
                     backend_id = 'suse'
-            self.__backend_path = (
-                os.path.splitext(__name__)[0]
-                + '.backend.'
-                + backend_id
-                + '.'
-            )
+            self.__backend_path = 'jw.pkg.lib.distros.' + backend_id + '.'
         return self.__backend_path
 
     def _instantiate(self, name: str, *args, **kwargs):
-        module = importlib.import_module(self._backend_path + name)
+        module_path = self._backend_path + name
+        try:
+            module = importlib.import_module(module_path)
+        except Exception as e:
+            log(ERR, f'Failed to import module {module_path} ({str(e)})')
+            raise
         cls = getattr(module, name)
         return cls(self, *args, **kwargs)