Dialaog manager

[leifoolsen]

Create a dialog manager .- to manage dialogs

[leifoolsen]

A dialog manager should:

• make the dialog a child of the html body element, if it is not already a child
• use the Material Design Lite Card component to provide a layout for the dialog
• if a dialog with same identity already exist, then the manager should update the dialog, not create a new
• check if a dialog polyfill is required
• attach click event listeners to button and anchor elements, or elements having a 'data-action' attribute
• emit a custom event when one of the 'clickable' elements is clicked