Add multiple UI elements

Add multiple UI elements, including:

Field of view slider
An in-game clock in the top left
UI to set the current time with number input
UI to change the speed of the simulation
A button to set the in-game time to the current time on the computer (real time).

With this update, the user practically has full control of the time in-game, without needing the Unity editor.

Merge after #41 has been merged, as this pull request relies on it.

amterp / COMP30019-Project-1