add university default github access token (#2486)

app/controllers/server/universities_controller.rb

app/models/communication/website/with_deuxfleurs.rb

app/models/university.rb

app/models/university/with_github.rb

app/views/server/universities/_form.html.erb

config/initializers/bugsnag.rb

config/locales/university/en.yml

config/locales/university/fr.yml

...095758_add_default_github_access_token_to_universities.rb

db/schema.rb

lib/tasks/app.rake