move spotlight container back to Scroller

Allow paging controls to opt-out of next neighbor determination so
focus can pass outside of scroller
exclude scroller from DataGridList spotlight handlers
exclude all non-client controls from spotlight handlers
Merge pull request #1618 from enyojs/CMB-1706-ryanjduffy

Fixes CMB-1706

Looks good!

Reviewed-by: Aaron Tam (aaron.tam@lge.com)