Update to JSON (Meta) Schema Version 2020

Our JSON Schemas right now are implementing the draft-7 (2016) JSON Meta Schema, which got some major updates since then. The current stable version is draft 2020-12.

pros:

• allow us to semantically seperate but technically bundle our Schemas in a smoother way. #49
• gives us the flexibiltiy of unevaluatedItems #3 (comment 2261822)

From a first check this should not introduce any breaking changes, and everything should continue validating the same. But we should test this.

further resources on Meta Schema Updating:

• JSON Schema 2020-12 Release Notes | JSON Schema (json-schema.org)
• GitHub - ajv-validator/json-schema-migrate: Migrate JSON-Schema draft-04 to draft-07, draft-2019-09 or draft-2020-12

assigned to @konstantin.walter

mentioned in issue #49

added To be discussed in meeting label

added Backlog label

removed To be discussed in meeting label

Call 21-07:

Important, but we need a stable 2.0 version first.

added TF-DP label