Persist user defined layout of the activities after saving pipeline--do not auto rearrange the activities layout upon reopening pipeline

Issue: rearrange your activities just the way you like it, save the pipeline, reopen the pipeline and all activities are rearranged to some default layout not matching your previous arrangement.

Motivation: it's annoying because if you have lots of activities and want to keep things visible according to your personal visual layout scheme, well, you have to start rearranging every single time you reopen the pipeline. If you have 10 or more activities, it gets really annoying as you want to go quickly about your task instead of messing around rearranging activity boxes every single bloody time because the default layout makes it more difficult to see what's going on (ofc everyone is different, but when you have a specific way to spatially organize boxes in a layout and if that's what you have visually memorized, it confuses you when you see it again organized totally differently).