Improve documentation for 508 Accessibility of Apps and Embedded Charts / Sheets

[Ken_T]

There does not appear to be any good documentation on how to configure qlik apps to be more 508 accessible.
All of the charts types should have documentation on how to make them work for handicapped users.
One example:  the container object, does not appear to be any way to access tabs via keyboard shortcut. There should be some way to use that object with keyboard shortcuts.