refactoring: use data_dir also for "work asynchronously" by mscolab UI

[ReimarBauer]

Currently with "work asynchronly" we store a file for an operation in the same top level dir as where we expect server data

~/mss$ tree -L 1
.
├── colabdata
└── local_colabdata

The flight tracks (without using mscolab) are stored in a user configurable data_dir (settings editor)

We should move the "work asynchronly" local_colabdata into that dir and look if we can change the filename so it is better readable (has operation name) in the flight track UI