Add optional initialization of base pose and feet pose in the Unicycle Trajectory Generator

[LoreMoretti]

This PR add the feature to initialize the unicycleTrajectoryGenerator with the initial base pose and the relative pose of the feet (which mimics what is done in TrajectoryGenerator.cpp in the generateFirstTrajectories member functions)

[S-Dafarra]

Look good to me! I would suggest adding a basic test for the additions

[LoreMoretti]

Look good to me! I would suggest adding a basic test for the additions

Thanks @S-Dafarra.

Indeed, when writing the new tests and compiling them, I found out that the signatures:

bool Planners::UnicycleTrajectoryGenerator::initialize(
    std::weak_ptr<const ParametersHandler::IParametersHandler> handler,
    const manif::SE3d& leftToRightTransform)


bool Planners::UnicycleTrajectoryGenerator::initialize(
    std::weak_ptr<const ParametersHandler::IParametersHandler> handler,
    const Eigen::Ref<const Eigen::Vector3d>& initialBasePosition)

seem to be ambiguous.

The only way I found so far is to pass initialBasePosition as const Eigen::Vector3d& instead of const Eigen::Ref<const Eigen::Vector3d>&. I know this reduces flexibility, but I could not find another way.

[GiulioRomualdi]

CI on conda fails with: #896