Secondary affiliations that are specific to an affiliation

[michaeljohansen]

Make it possible to have sub-affiliations that are only visible to the parent affiliation. E.g. Teaterlosjen should be the only affiliation that is able to choose "Universitetsteateret" as a secondary affiliation. Same goes for A/F Smørekoppen and their sub-affiliation "Industrivinduet" (which is currently commented out).

[michaeljohansen]

For now I have added Industrivinduet as a regular affiliation.