Create share buttons for WhatsApp and Twitter

[juanbelieni]

From issue #1

What I did:

• I created two buttons: one for WhatsApp and another for Twitter.
• I created a class for icons, that is a container for the three existing icons.

Problems:

• I couldn't find a way to share via Instagram DM, so there is no button for it.

[vercel[bot]]

@juanbelieni is attempting to deploy a commit to a Personal Account owned by Bram Musuko Panjaitan on Vercel.

@bmusuko first needs to authorize it.

[bmusuko]

LGTM!