Sort out CodeLocation and JarvisConfig in relation to Jarvis.dws Autostart

Currently, if Jarvis is loaded using the Jarvis.dws workspace, relative file paths are determined from the workspace location. This has some implications for the dyalog/jarvis container because it uses that workspace. I believe a more flexible (and user friendly) solution would be to use the location of the JarvisConfig file, if it exists, as the root folder from which relative folders are found. This makes Jarvis apps more portable.