FEAT: Permalink for a preset scenario

Add the ability to share a link to a scenario (code, initial registers, initial PC, placed nodes) via a link, such that the info will be after the `#` - e.g.
```
https://yontank.github.io/MipsVisualizer#scenario/{code:"add $1, $2, $3", ...
```
The data could be encoded or compressed maybe.
This might be related to #43 .