Add a zoom/full screen button for image of tokens

[Agilulfo1820]

On the ERC 721 token page, we can see the image of the token taken from the metadata. I think it would be useful to have a button to see the image in full-screen mode. What do you think?

[vbaranov]

That is a good idea! Or even to make image clickable and open its original link in a new tab. If you can prepare a PR, I'd love to review/merge it to master branch.

[Agilulfo1820]

I'll try this weekend, but I never used elixir nor erlang before so I hope I'll be able to grasp it fast.