Build rendered Certificate view

[bedinotti]

This is the visually designed display that looks like a real certificate.

[bedinotti]

The placeholder view for this is complete:

However, I don't really want to consider this task done until that view is a bit more refined.

[bedinotti]

I created a first draft on community guidelines for displaying certificates. I need to:

• Get feedback on the proposed large & small designs
• Move that post to something in the blockcerts domain, so others can see it
• Re-render the images with a published certificate that others could use to test their rendering.

I also updated the display to look a bit more respectable. But not much.

[bedinotti]

I'm going to call this good enough to ship. Display has been updated so it's fully responsive, and renders consistently on different device sizes. I also added in the description.

Signatures have been removed. I'm going to wait to add those back in until we iterate the format to formally support titled signatures. And even then, it may not make it to the mobile display.