Custom interface for configuring dac

[michaeljyeates]

The dac configuration page is currently showing a generic ui, we can group many of the items to make it much more usable. We also need a custom widget to display an extended symbol

[michaeljyeates]

When the config change is submitted to the custodians, it should include text which explains exactly which config variables have changed. eg.

Number elected : old value = 3, new value = 7