Move to collective?

[pgrunewald]

Since the name collective.deletepermission already suggests that this add-on belongs to collective it would consequential to move it to that organization. That way, other contributors can accept pending pull requests (see #21 and #20).

One additional question is, who has authority to publish to pypi? I'd volunteer to do so. For now it doesn't seem, that there is a too busy release schedule.