feature: add parsing of task_id, test_code and user_output to bring test-runner to v3

[vaeng]

Introducing the task_id, test_code, and user output into the test runner is a rather significant change, but necessary to get the track tooling to v3.

This PR enables passing the task_id as a tag in test cases.

task_id usage

It is currently limited to 99 tasks.

TEST_CASE("divisible_by_400", "[task_3]") { ... }

New Catch2 version usage

To get the tag from the Catch2 testing framework, the framework had to be updated to version 3.0+.
This requires a new include in the test files.

#ifdef EXERCISM_TEST_SUITE
#include <catch2/catch.hpp> // Catch2 v2.0+
#else
#include "test/catch.hpp"
#endif

to:

#ifdef EXERCISM_TEST_SUITE
#include <catch2/catch_all.hpp>  // Catch2 v3.0+
#else
#include "test/catch.hpp"
#endif

The test-runner will change the old include to the new header automatically, so no changes for existing exercises are necessary.

Output usage

Students can now output their debugging via std::cout. The result is visible in the output field in the final json file.

test_code implementation

The test code comes from scanning the test file from one test to the next. It deletes common code elements that might appear between to test case bodies, but not everything. So keep your tests clean 😄

Reasons for the changes

The current framework is version is limited and will not be easy to publish results as specified in the v3 test runner.

The tag is not shown in the current junit testing reporter and had thus to be switched to pure XML.
Instead of rewriting the Python parser to accommodate the changes, a new cpp parser was written.

To use modern C++17, the alpine version of the container was updated as well. This asked for some of the expected_results.json to change to mirror the new error messages from the system correctly.

Maintainers thus do not need to know about Python to take care of the cpp track and the parsing is faster.
A future advantage might be using smaller docker images, that do not need a Python installation.

[ErikSchierboom]

LGTM!