Business layer method to get error message as HTML updated

The business layer finBL.GetHtmlErrorMessage method has been updated to embed the error icon rather than try to get the icon from the file system.

The error image now uses a data url which is compatible with finPOWER Connect Cloud.

Also fixed an HTML formatting issue where the head and body tags were in the wrong order; this never appeared as a visible issue when viewed from within finPOWER Connect.