Simple interface version 0.1

Create a first version of the interface, which will be a proof of concept for using PyQt6 to generate an interface for a video player. It should look like this:

The user should be able to:

• Load arbitrary video files via a menu
• Toggle normal/full screen view with a keystroke
• Start/pause the video with the space key
• When the video is paused, show next/previous frames when right/left arrow keys are pressed
• The timeline bar must go from zero to the total duration of the video (the time ticks must be shown)
• The current position of the video must be indicated (by colors, in the mockup above, but can be a simple vertical line)
• The position in the video can be changed by clicking in the timeline bar