[a11y] keyboard interaction for tooltip

[Etat-Plateforme]

According to http://www.w3.org/TR/wai-aria-practices/#tabpanel
Escape key shoud dismiss the tooltip.

[wesleycho]

Is this for the tooltip? Please put more detailed information when opening issues.

[pkozlowski-opensource]

@wesleycho I think it is for tooltip:

Escape key shoud dismiss the tooltip.

[wesleycho]

Linking this for reference: http://www.w3.org/TR/wai-aria-practices/#tooltip

In particular, this requires tooltips being tracked in a global data store - $$stackedMap from the modal service needs to be used, so that needs to be separated into a new module.