Add a __main__ to cubicweb This avoids calling cubicweb-ctl relatively in tests and could be useful in virtualenv. This is just a copy of bin/cubicweb-ctl file, which should probably be generated from a setuptools entry points.

Release notes
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.. toctree::
    :maxdepth: 1

    3.22
    3.21
    3.20
    3.19
    3.18
    3.17
    3.16
    3.15
    3.14