add dbpedia_14 dataset
Thanks for the review. 
Cheers! Hi @hfawaz, this week we are doing the 🤗 `datasets` sprint (see some details [here](https://discuss.huggingface.co/t/open-to-the-community-one-week-team-effort-to-reach-v2-0-of-hf-datasets-library/2176)).

Nothing more to do on your side but it means that if you register on the thread I linked above, you can have some goodies for the present dataset that you have already added (and a special goodie if you want to spend more time and add 2 other datasets as well).

If you want to join, just tell me (or post on the thread on the HuggingFace forum: https://discuss.huggingface.co/t/open-to-the-community-one-week-team-effort-to-reach-v2-0-of-hf-datasets-library/2176) Hello @thomwolf 
Thanks for the feedback and for this invitation, indeed I would be glad to join you guys (you can add me). 
I will see if I have the time to implement a couple of datasets. 
Cheers!  @hfawaz invited you to the slack with your uha email.

Check your spam folder if you can't find the invitation :) Oh thanks, but can you invite me on my gmail: hassanismailfawaz@gmail.com 
UHA is my old organization, I haven't had the time to update my online profiles yet.
Thank you 
This dataset corresponds to the DBpedia dataset requested in https://github.com/huggingface/datasets/issues/353.