lib.ExecContext.__init__(): Add parameter uri

Take a positional uri argument to the constructor of ExecContext,
forcing SSHClient to follow suit. The latter was instantiated with a
hostname as only argument up to now, which still works as a special
case of an uri.

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

src/python/jw/pkg/lib/ec/Local.py

@@ -11,6 +11,9 @@ from ..util import pretty_cmd
 
 class Local(Base):
 
+    def __init__(self, uri='local', *args, **kwargs) -> None:
+        super().__init__(uri, *args, **kwargs)
+
     async def _run(
         self,
         args: list[str],