Renommage du bloc portfolio en projets (#1717)

...assets/images/communication/blocks/templates/projects.jpg

...ges/communication/blocks/templates/projects/alternate.png

...s/images/communication/blocks/templates/projects/grid.png

.../images/communication/blocks/templates/projects/large.png

...s/images/communication/blocks/templates/projects/list.png

app/models/communication/block.rb

app/models/communication/block/template/portfolio/element.rb

app/models/communication/block/template/project.rb

app/models/communication/block/template/project/element.rb

...in/communication/blocks/templates/projects/_edit.html.erb

...in/communication/blocks/templates/projects/_show.html.erb

...communication/blocks/templates/projects/_snippet.html.erb

.../communication/blocks/templates/projects/_static.html.erb

config/locales/communication/contents/en.yml

config/locales/communication/contents/fr.yml