feat: add SolverConfigOverride support for setting the time spend directly

[PatrickDiallo23]

Summary

This PR aims to add support for setting the time spend directly, without relying on manually creating a TerminationConfig object (#1254).

Added withTerminationUnimprovedSpentLimit and withTerminationSpentLimit methods in the SolverConfigOverride class. Also, I added 2 tests to ensure code coverage and a proper functionality.

Example

solverFactory.buildSolver(new SolverConfigOverride<VehicleRoutePlan>()
                .withTerminationSpentLimit(...)));

# OR

solverFactory.buildSolver(new SolverConfigOverride<VehicleRoutePlan>()
                .withTerminationUnimprovedSpentLimit(...)));

[triceo]

Thanks for the contribution!
I've asked some questions in the comments inline, let's have a conversation about this design.

[PatrickDiallo23]

@triceo I updated the API as we discussed. I tried to provide a comprehensive documentation so that it will be easier for developers to understand how to use the methods. Please let me know if I used a good approach and if I should also add other unit tests (and where: in the other modified file or I should create SolverConfigOverrideTest class)?

[triceo]

LGTM when the comments are improved!

[PatrickDiallo23]

@triceo I made the changes. I hope everything is better now.

[triceo]

Thank you, Patrick!