Add fact statement JSON examples to test suite

[peterVG]

Create one or more sample fact statements, including a schema structure, to use as a test fixture in development.

[GeorgeFlerovsky]

In the tutorial, we have included several simple JSON examples for the reader to interactively insert into the Fact Statement store of the back-end service of a COOP publisher.

The schema structure of fact statements is not in scope for COOP. The publisher is assumed to use an external framework to manage the schema structure of fact statements.

If you like, you can add some JSON files to the repository and incorporate them in the test suite. 👍