[FEATURE] sap.ui.commons.MenuBar: Introduce F6 handling

Change-Id: Id31540aedf5eab62cd0c24479cf99b19e1b420b4
[FEATURE] sap.ui.ux3.Shell: Introduce F6 handling

Change-Id: Idd8854eca5862e89c59efcb69e7de217e1404b1a
Merge "[FEATURE] sap.ui.commons.MenuBar: Introduce F6 handling"
Merge "[FEATURE] sap.ui.ux3.Shell: Introduce F6 handling"