Pathing in metadata.json

[DavidDierickx]

The pathing in the simulation metadata files when run on Massive obviously point towards the relative Massive path, which means when transferred off the HPC you can't use the UI to visualise them without going into each simulation and modifying the paths to where the simulations are now stored. Not sure on the best practice here, whether to supply both paths or some other solution, just raising it now as it will probably need to be solved.