Denix

taking into account that ```perl_lib/EPrints/Plugin``` and ```lib/plugins/EPrints/Plugin``` are overridden at every upgrade, so they are unusable as a central folder.

For example, in my development machine I have a file called `archive/{archive}/cfg/cfg.d/0_devel.pl` where I set the level of noise. I understand, perhaps setting the loglevel to 4 is too much,...

Sorry, I just realized I forgot the comment line in my pull https://github.com/denics/eprints/commit/2175f0f597b7c3e40d255afe420219226a920243

A partial solution has been the creation of a label by @jesusbagpuss in issue #422