Use omeroweb.webclient.decorators rather than omeroweb.webstart.decorators
Use omeroweb.webclient.decorators rather than omeroweb.webstart.decorators

This should should restore the compatibility of the weberror OMERO.web app
with the 5.0.x line of OMERO.web and simplify deployment on the CI
infrastructure.

openmicroscopy/weberror,openmicroscopy/weberror