Outputs Update

[rhinoella]

Reform the way Gudrun is run and the way the outputs are handled.

• Have all the output files stored and organised in a directory
• Have Gudrun dcs always run in a temporary directory and copy the files out of it
• Have purge run in a temporary directory and place purge files in project directory
• Update Nexus Processing to not need the temporary/writable directory options
• Allow the project directory to be reloaded into Gudpy to continue work