Fix conflicting validators

[christophfroehlich]

Combination of lower and upper bounds resulted in invalid ROS code

          rcl_interfaces::msg::ParameterDescriptor descriptor;
          descriptor.description = "specifies maximum acceleration limits for x, y and z axis";
          descriptor.read_only = false;
          descriptor.floating_point_range.resize(1);
          descriptor.floating_point_range.at(0).from_value = -10.0;
          descriptor.floating_point_range.at(0).to_value = std::numeric_limits<double>::max();
          descriptor.floating_point_range.resize(2);
          descriptor.floating_point_range.at(1).from_value = std::numeric_limits<double>::lowest();
          descriptor.floating_point_range.at(1).to_value = 10.0;

where floating_point_range must not be of size greater 1.
It throws std::length_error("Exceeded upper bound") (but bounds of this vector size, not of the declared parameter) resulting in

1: unknown file: Failure
1: C++ exception with description "Exceeded upper bound" thrown in SetUp().

This PR adds build-time errors for this unsupported combination. I don't see a point in auto-merging it, users of this lib are simply encouraged to just use the correct validators.

Fixes #334

[christophfroehlich]

👀 @vincent-daniele