Add Wallabag integration

http/client.go

integration/instapaper/instapaper.go

integration/integration.go

integration/pinboard/pinboard.go

integration/wallabag/wallabag.go

locale/translations.go

locale/translations/fr_FR.json

model/integration.go

scheduler/scheduler.go

server/template/html/integrations.html

server/template/views.go

server/ui/controller/integrations.go

server/ui/form/integration.go

sql/schema_version_11.sql

sql/sql.go

storage/integration.go

storage/migration.go