[ic-time-selector] Add pageup/down functionality

[GCHQ-Developer-718]

Summary

Add a pageup/down listener that increases/decreases the selection in the focused column by 10.

💰 Use value

It's a standard keyboard interaction behaviour that will make it significantly easier for keyboard-only users to change their selection using arrow keys.

10 is a bit of a magic number. It's a consistent recommendation from W3C but using 10 specifically isn't required. If a different number seems more suitable during testing, the developer should feel free to use a different number.