scripts/qmp-shell: move to python/qemu/qmp/qmp_shell.py

scripts/qmp-shell: move to python/qemu/qmp/qmp_shell.py

The script will be unavailable for a commit or two, which will help
preserve development history attached to the new file. A forwarder will
be added shortly afterwards.

With qmp_shell in the python qemu.qmp package, now it is fully type
checked, linted, etc. via the Python CI. It will be quite a bit harder
to accidentally break it again in the future.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210607200649.1840382-41-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>