Add Bilingual Corpus of Arabic-English Parallel Tweets
IMO, the problem with this dataset is that it is not really a text/nlp dataset. These are just collections of tweet ids. So, ultimately, one needs to crawl twitter to get the actual text. That's true.

 at least it's clear in the description that one needs to collect the tweets : 
```
This resource is a result of a generic method for collecting parallel tweets.
``` Looks like this is failing for other datasets. Should I rebase it and push again?
Also rebasing and pushing is reflecting changes in many other files (ultimately forcing me to open a new branch and a new PR) any way to avoid this? No let me merge this one directly, it's fine merging since the CI is fixed on master
Added Bilingual Corpus of Arabic-English Parallel Tweets. The link to the dataset can be found [here](https://alt.qcri.org/wp-content/uploads/2020/08/Bilingual-Corpus-of-Arabic-English-Parallel-Tweets.zip) and the paper can be found [here](https://www.aclweb.org/anthology/2020.bucc-1.3.pdf)

- [x] Followed the instructions in CONTRIBUTING.md
- [x] Ran the tests successfully
- [x] Created the dummy data