feeble attempt to display room names in mobile view

[hypha]

An attempt to show room names in mobile view and resolve https://github.com/EuroPython/website/issues/667. Currently, it has a separate row instead of being inside the each session's grid. But it might still be readable. For registration sessions, the name is not displayed in mobile view as it is already in session title.

[patrick91]

I've made a different implementation in #754, it's similar to last year 😊