Revert "Revert "Limit thanks for new users at pl.wikipedia to 3 per day""
The pl.wikipedia thanks feature is again abused, soon after the revert.
The wiki contributors interested by the question testimonied
social actions don't give satisfactory results, and would be
in favour of a permanent limit for new contributors.
As such, the sensible thing is probably to reenable the limit
for a longer term.