Enable Piwigo publishing by default.  Closes #4802.
Enable Piwigo publishing by default.  Closes #4802.

polymeris/shotwell,h4ck3rm1k3/shotwell,ritchiewilson/shotwell,Sanva/shotwell-gsoc,ritchiewilson/shotwell,jimbonator/shotwell,abrauchli/shotwell,Sanva/shotwell-gsoc,abrauchli/shotwell,polymeris/shotwell,damianmoore/shotwell,h4ck3rm1k3/shotwell,h4ck3rm1k3/shotwell,jimbonator/shotwell,jimbonator/shotwell,Sanva/shotwell-gsoc,damianmoore/shotwell,damianmoore/shotwell,ritchiewilson/shotwell,polymeris/shotwell,abrauchli/shotwell