Update migration docs and normalize API keys

Documentatie voor migratie toegevoegd, scripts makkelijker gemaakt en de keys allemaal hetzelfde gemaakt.

Zie ook thalia/website!590, die moet eerst

See merge request !128

Remove pdb



See merge request !127

Import events



See merge request !126

This reverts merge request !124

Import events

Should work, someone else should take a look at it.

See merge request !124

Add wiki login api

Partially implements #101 

Still needs the accompanying wiki plugin to be written (blergh, php)

See merge request !122

Fix the `is_staff` setting check

It tried to check the wrong related set (not sure what set, actually).

See merge request !123