Support comma separated list values in --exclude argument

[ppham-nv]

Previously we had to add a separate --exclude flag for each lib:

auditwheel repair test.whl --exclude=liba.so --exclude=libx.so

This PR allows passing in multiple libs as a comma separated list:

auditwheel repair test.whl --exclude=liba.so,libx.so

[ppham-nv]

Travis CI infrastructure issue since it cannot pull python:3.9-slim-bullseye container for s390x but test passes on aarch64?

https://app.travis-ci.com/github/pypa/auditwheel/jobs/626999921#L20476

ERROR tests/integration/test_manylinux.py::TestManylinux::test_build_repair_numpy[manylinux_2_17] - docker.errors.ImageNotFound: 404 Client Error for http+docker://localhost/v1.43/images/python:3.9-slim-bullseye/json: Not Found ("No such image: python:3.9-slim-bullseye")
ERROR tests/integration/test_manylinux.py::TestManylinux::test_build_wheel_with_binary_executable[manylinux_2_17] - docker.errors.ImageNotFound: 404 Client Error for http+docker://localhost/v1.43/images/python:3.9-slim-bullseye/json: Not Found ("No such image: python:3.9-slim-bullseye")