Catalogue- Structure for results

[cliftonc]

In discussion with @mcginkel it is clear that for progress and results to be exchanged, the LMS and LA need to agree a basic level of structure about the product itself to enable this exchange to happen.

The basic catalogue is defined: https://stichtingsem.stoplight.io/docs/sem-technology-prototype/branches/learning-application-catalogue/reference/catalogue.v1.yaml for commercial usage (e.g. so a school can see, select, purchase).

The LMS requires more detail, thoughts:

• Atomic: It needs to support the simplest model - e.g. the LA is a single activity (e.g. it starts, finishes, and has a result that is passed back) - like a typical LTI exchange.
• MultiStep: It needs to support more complex models - e.g. the LA provides a set of activities or assignments that the learner can progress through over time, so progress and results should be exchanged about the activities.

Related: #17 (comment)