Add twitter card metadata

[jeremenichelli]

I think we could easily introduce some metadata to display better content when docs are shared on twitter, nothing big but a nice to have I guess.

[montogeek]

Definitely, always nice to have.

[jeremenichelli]

I can put a PR soon about this, so I will assign this to myself.

[EugeneHlushko]

@jeremenichelli hi man, i hope you dont mind i've put up a PR for this as it was kinda stalled for a while (last action 5th of April)

[EugeneHlushko]

in rebuild now 🎉