feat: as data manager I would like to inspect all my data in the preview instead of only 10x10

[marikaris]

Motivation:
data manager now only sees 10x10 preview and that gives insecurity if the whole data is now loaded correctly
Demo:
ability to see all columns and optionally also more rows
Acceptance criteria:
probably requires pagination / scroll+load
alternative, do a listing of the columns without showing the data
Notes:
need to extend the endpoint to allow more.