Parameter support

Something like (this doesn't work as is)
```julia
function parameter_int(name, value::Int)
param_ref = Ref(LibScoreP.SCOREP_USER_INVALID_PARAMETER)
LibScoreP.SCOREP_User_ParameterInt64(param_ref, name, value)
return nothing
end

function parameter_uint(name, value::UInt)
param_ref = Ref(LibScoreP.SCOREP_USER_INVALID_PARAMETER)
LibScoreP.SCOREP_User_ParameterUint64(param_ref, name, value)
return nothing
end

function parameter_string(name, value::AbstractString)
param_ref = Ref(LibScoreP.SCOREP_USER_INVALID_PARAMETER)
LibScoreP.SCOREP_User_ParameterString(param_ref, name, value)
return nothing
end
```

Be wary of of https://github.com/score-p/scorep_binding_python/issues/146.