Tests facility

I have added the Lorenz test of Rouson's book. Here we create a list of desired test
- pure ODEs:
- [x] Lorenz equations, see [wiki documentation](https://github.com/Fortran-FOSS-Programmers/FOODiE/wiki/Lorenz-equations), test [sources](https://github.com/Fortran-FOSS-Programmers/FOODiE/tree/master/src/tests/lorenz);
- [x] Oscillation equations, see test [sources](https://github.com/Fortran-FOSS-Programmers/FOODiE/tree/master/src/tests/oscillation);
- PDEs:
- [x] Burgers equation, see test [sources](https://github.com/Fortran-FOSS-Programmers/FOODiE/tree/master/src/tests/burgers);
- [x] 1D Euler equations;
- [x] 1D Euler equations solved with OpenMP enabled code;

Review the existing tests under src/tests/lorenz, src/tests/oscillation, and src/tests/burgers, along with the linked Lorenz documentation. Then determine whether the listed 1D Euler and OpenMP-enabled Euler tests are already complete; the facility is done when the desired ODE and PDE test coverage is clearly implemented and verifiable.

Written by the indexing model from the issue text.