Feature: Slider for clock position

User should have control padding of clock on the new tab screen.

### Suggestions:
- [ ] slider for x and y position
- [ ] position data should be in percentage unit
- [ ] position data should persist

Start at the new tab screen and locate how the clock position is rendered and where its settings are stored. Add controls for horizontal and vertical position using percentage values, then verify that both positions remain unchanged after reopening or reloading the new tab screen.

Written by the indexing model from the issue text.