Remove dropdowns from datasets

[stefanodavid]

Describe the issue Dropdowns should be removed and boxes with the information about each dataset should avoid scrollbars.

http://opendatahub.readthedocs.io/en/latest/datasets.html#datasets-in-the-mobility-domain http://opendatahub.readthedocs.io/en/latest/datasets.html#datasets-in-the-tourism-domain http://opendatahub.readthedocs.io/en/latest/datasets.html#datasets-in-other-domains