UX: Make Fillup Ether Easier

[skywinder]

To simplify user interaction with Rinkeby network: We do automation work that described here: https://www.rinkeby.io/#faucet

• Add button to fill up test ether.
• by clicking on the user can pass Authentification on Facebook/Twitter/Google.
• We are making a public post with his Rinkeby address, that capture from Metamask
• Grab a link to this post and provide user easy way to copy
• show instructions, what to do next: Go to https://www.rinkeby.io/#faucet and fill up the form.

[skywinder]

fyi, @bykrab