web/application: instantiate the repository outside of CubicWebPublisher
This improves decoupling and allows ``CubicWebPublisher`` user to choose which
argument are used during ``Repository`` instantiation. In particular is allows
caller to provide a ``TaskManager``.
The `vreg` argument of publisher is made mandatory. See CubicWebPublisher
docstring for details.
Related to #2249513
include *.py
include */*.py
recursive-include data *.gif *.png *.ico *.css *.js
recursive-include i18n *.po
recursive-include wdoc *