A better way to configure CSP and disable unsafe-inline

I found a better way to configure CSP that does not require unsafe-inline overwrite 

1. In initializer add a CSS class instead of inline style:

```
html: '<div id="%<id>s" class="dashboard-chart">%<loading>s</div>'
```

2. add your css class (height, alignment font etc)


Works if you can have same style across all charts. 