Add timer functionality to draw-sketch view

[HenriScaff]

Currently, the draw-sketch view just has placeholder text for the timer "00:00".

Add functionality to:

• count down from 10 (can decide on the specific number at later date) when the page is loaded
• when the timer runs out, run the functionality of the submit button

[HenriScaff]

Done. I also added a begin button so the timer doesn't just count down as soon as the page is loaded. Once the begin button is pressed, the timer counts down and the user can draw, change colour and submit. When time runs out and/or the submit button is pressed, the drawing is "submitted" (placeholder functionality at this stage) and the page is reset to its state before the begin button was pressed.