Could be made clearer in documentation that transformation is saved after uploading file

[bcouston]

After uploading a file and creating a new data transformation, the transformation is saved automatically. This makes it quite easy to clutter the list of transformations a user has made, especially in combination with #46. From a user's point of view this should be made clear in documentation (https://datagraft.net/documentation/) or even omitted altogether and let the user save it themselves.

[fungiboletus]

Is using the uploaded filename as part of the transformation title good enough? We can also remove the necessity to save the data transformation but it's a lot of work.

The documentation was written before this behavior was implemented. We need to update the documentation soon.