Add join_main_foreninger template tag

This joins the main foreninger of a given forening by name, default
joined with 'og', and returns the resulting string
Display the correct publication parent forening(er)
forenings -> foreninger
Add initial campaigns section boilerplate
Add initial campaign model
List existing campaigns
Add initial 'new campaign' page
Implement image upload
Add js wrapper
Move campaigns under sites section
Add informational paragraph
Rephrase button
Add site field to campaigns
Add pick from image archive option
Rephrase breadcrumb label
Add section-progress
Rephrase text and labels
Add hidden second step
Add third step
Use single quotes