Add the Dirac distribution from OpenTURNS

This Dirac distribution can be very useful to check the consistency of UQ techniques when the variance tends to zero. We could add the Dirac distribution from OpenTURNS. Actually we can use it with:

from gemseo.algos.parameter_space import ParameterSpace

space = ParameterSpace()
space.add_random_variable(
    "x",
    "OTDistribution",
    interfaced_distribution="Dirac",
    parameters=(1.5,),
)

but it would be much easier to write:

from gemseo.algos.parameter_space import ParameterSpace

space = ParameterSpace()
space.add_random_variable("x", "OTDirac", value=1.5)