Are there any comparable features in LC ES like the
"import/export LAR project file" features in LC 7.x (etechui)? I know,
etechui doens't exist anymore... but in my opinion there should be an "export/import" support anyway. We are setting up several environments (such as test, integral test, production, etc.). Do we really have to configure and set up all the "workbench work" (e.g. creating processes) for each environment?
Yes, there is such a feature.
You can export a LAR file from Workbench - just right click on your process. It contains all the things you need to reconstitute it on the other end, including process, forms, and non-standard components.
At the other end, you import it using Adminui, rather than Workbench.
I guess the reasoning is that developers do the exporting, and administrators do the importing into production. In practise, it's a bit confusing that it's not orthogonal, but it does actually work quite nicely.
Note that you do have to set up any end-points again if necessary, and possibly set security/permissions.