Add licensing information in REUSE format

.gitignore

.gitlab-ci.yml

.reuse/dep5

COPYING

LICENSES/GPL-3.0-or-later.txt

LICENSES/LicenseRef-AutoconfArchiveException.txt

LICENSES/MIT.txt

Makefile.am

autogen.sh

configure.ac

dbus-python.pc.in

dbus/_compat.py

dbus/types.py

doc/redirects.py

test/import-repeatedly.c

test/test-exception-py3.py

test/test-server.py

tools/check-c-style.sh

tools/check-coding-style.mk

tools/check-py-style.sh