Modal accessibility

Focus getting lost when modal dialog is closed by using Close button.

• Add role dialog to container. Also add tabindex -1 so it can be focused by js and thus announced by screen reader.
• Fix keyboard detection, there is no "e.key" value Space.

• Add aria-labelledby to the dialog.
• Modal title should be heading not div.
• Add role close to close link(button).

• When the dialog is visible and the focus has been moved on it, the keyboard focus must remain within modal dialogs when open.

• The initial focus should be on the dialog container with role="dialog".