Add GraphQL queries for FunctionDefinition and ParameterDefinition

[Taucher2003]

The new types (non-runtime types) from #354 need to be queryable over GraphQL

[nicosammito]

We need to talk about this, because maybe that’s just an internal process

[Knerio]

We need to talk about this, because maybe that’s just an internal process

But the frontend should be able to request it, right?

[nicosammito]

We need to talk about this, because maybe that’s just an internal process

But the frontend should be able to request it, right?

Access yes, but mutations are not needed from Frontend side

[Knerio]

So we would still need to setup the queries, right?