fix(ui5-select): Selection now changes instantly

[vladitasev]

In order for the selection to be smooth, the focus/selection handling should be done internally by the list. Otherwise the select will always be one step behind and the focus will always lag behind the selected item.

Changes:

• The list gets a new mode: SingleSelectAuto that changes the selection when the user presses the arrows. So in fact the focused item is always selected (automatically, hence the name).
• The select uses the new list mode and handles selection change and item click. The only difference is that on selection change the popup is not closed and on item click it is.
• The keyboard handling code that used to be in one function for both modes (when popup closed, when popup open) is now naturally split in 2 parts: when the popup is open, handle only esc/enter, as the list already handles everything else internally, and when the popup is closed, handle only arrow up/arrow down.

closes: #1992

[ilhan007]

Works perfect!