Description Tobias Wenzel 2022-10-27 16:50:31 CEST

## Story

As an administrator of a UCS@school domain
I can attach arbitrary roles with custom context types to my school objects,
so that I can implement custom logic.

## Context/description

Currently the school lib throws errors if a school object has roles that do not have the context type `school` or `exam`. The lib also checks some additional requirements, like the use of only defined role names. In reality we want the following situation though:
- If a role with the context type school or exam is used, we want to enforce all current rules and throw errors as before
- Any other role string, which has an unknown context type, is allowed and will simply be ignored.
- All role strings still have to follow the triple segment syntax (role:context_type:context)

Additional points:

- This has to be changed both in host ucsschool lib and kelvin!
- This affects the get_role_info and create_role_string function in the ucsschool lib

## Acceptance criteria & steps for reproduction

- Arbitrary context types are allowed
- The Kelvin changes are available at least in the test appcenter
- The changes to ucsschool **have been released** as an errata