scripts/ and cronscripts/ should be generated as setuptools entry-points

[Celso Providelo]

As Barry commented in https://code.edge.launchpad.net/~cprov/launchpad/cronscript-checker/+merge/9175, it would be much easier to maintain the scripts we ship in launchpad (scripts/ and cronscripts/) if they were generated as application entry-points by buildout.

We can do and experiment with a well-formed script and see how it goes.

buildout.cfg
{{{
[scripts]
...
entry-points = copy-package=lp.soyuz.scripts.packagecopier:main
...
}}}

That would create `bin/copy-package` (once we write main())