Allow to define paths that should be swallowed, e.g '/erp5/web_site_module/foo'.

Don't use this, but use slapos.recipe.certificate_authority
from the instance profile.

Then only allow what's in htdocs.

And use absolute paths everywhere.

After Vincent's review

After Vincent's review

development profile
software (production) profile
common (not pinned) profile.

Conflicts related to URL changes:
	component/imagemagick/buildout.cfg
	component/libtiff/buildout.cfg
	component/rpm2cpio/buildout.cfg

name is confusing at first.

(cherry picked from commit e154f063)