add social thumbnial
# What does this PR do?

I added OpenGraph/ Twitter Card support to the docs to create nice social thumbnails.

![Bildschirmfoto 2021-04-07 um 08 36 50](https://user-images.githubusercontent.com/32632186/113821698-bac2ce80-977c-11eb-81aa-d8f16355857e.png)

To be able to add these I needed to install `sphinxext-opengraph`. I came across this [issue](https://github.com/readthedocs/readthedocs.org/issues/1758) on the readthedocs repo saying that since someone has built this plugin they are not integrating and providing documentation to it. That's why I added it for creating the documentation. The repository can be found [here](https://github.com/wpilibsuite/sphinxext-opengraph/tree/main).

P.S. It seemed that `make style` never ran for `docs/` i hope the changes are okay otherwise I'll revert it. 