Rename app to avoid naming conflicts

[AWolf81]

At the moment, GraphvizApp is in conflict with graphviz.org. And to avoid conflicts I'll rename it to
DrawViz for now.

I'll also change the surge.sh address to https://drawviz.surge.sh. (published)

I've anyone has a better idea for a name please let me know. But I think it's OK to start with.

Some points that could be part of the name:

• Graphviz
• Dot
• Viz.js
• Draw
• Render