[WIP] Buildout parts to run nostests against target dbs

Alternative approach to https://github.com/geoadmin/mf-chsdi3/pull/738

This PR add two new _buildout_ part to run _nosestest_ against the planned target DBs.

To test the integration DB:

     ./buildout/bin/buildout  -c buildout_dev.cfg install nosetests-int

To test the production cluster:

     ./buildout/bin/buildout  -c buildout_dev.cfg install nosetests-prod

The _nosetests-template_ is there to modifiy the _production.ini_ only, to minimize problems if someone is restarting apache2 during the test.