We should move all of this HTML to a TPL constant as well.
For the areas that will need dynamic insertion, you can use A.Lang.sub(), which will allow you do to something like:
```
var TPL_PANEL = '<li class="user user-{panelId}" panelId="{panelId}">' + ...;

var html = A.Lang.sub(
    TPL_PANEL, 
    {
        panelId: instance._panelId,
        ...
    }
);
```