Using schemas for explicit input and output types results.json

[silvandeleemput]

Description

The input and output types should be made explicit for the processor and evaluator once the schemas are publicly available through comic/grand-challenge.org#1017.

For input and output type support in the results.json we would like:

• Create a simple interface for fetching datatypes schemas on grand-challenge  grand-challenge.org#1017 should be implemented first
  • Fetch and cache the schemas for the input and output typing
• Make typing of inputs and outputs explicit
• Fix input and output types for the processor template
• Fix input and output types for the evaluator template
• Properly test everything

[silvandeleemput]

We won't continue this, see #309 for the new approach for input/output types