Disable Settings dialog 'Submit' button if invalid

Use Angular's <form>-directive for out-of-the-box validations.

Bug # 9901

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Fix broken label for attribute in Settings dialog

To avoid having to define an id, wrap label around input element.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Display required asterisk in Save dialog label

Bug # 9901

Signed-off-by: Alex Coles <alex@alexbcoles.com>