Allow to launch the multi system propagation as normal td runmode
So far we are launching the new multi-system propagation through a test. This MR move this code to run.F90 and allows to launch the multi-system propagation with CalculationMode = td. If all systems defined in the input file have a new multi-system implementation then this will be used, otherwise the old behaviour is used for the runmodes.
- I have checked that my code follows the Octopus coding standards
- I have added tests for all the new features added in this request.