[GSOC 24] qt: reintroduce minimal mode

The Minimal View refers to a user interface mode designed to provide a simplified and more focused view of the player’s core functionalities. This mode typically reduces the clutter by hiding or minimizing non-essential elements, allowing users to concentrate on the media content. Here’s a general overview of what the Minimal View in VLC might involve:

Key Features of Minimal View in VLC

• Compact User Interface: The Minimal View mode streamlines the interface, often by reducing the size and number of visible controls. It typically focuses on essential playback controls like play/pause, stop, and volume.
• Reduced Controls: Non-essential controls, such as advanced settings, playlists, and detailed media information, are hidden. The goal is to provide a clean, distraction-free interface for users who prefer simplicity.
• Improved Focus on Content: By hiding extraneous controls, the Minimal View emphasizes the video or audio content. This can be particularly useful in scenarios where the user wants to maximize screen space for media playback.
• Customizable Appearance: VLC allows some degree of customization in Minimal View mode, letting users adjust which controls are visible and their layout. Users might have options to toggle between Minimal View and other more detailed views.

Implementation in VLC

In VLC, the Minimal View can be activated through several mechanisms, including:

• Qt Interface: The Qt interface of VLC have a built-in Minimal View settings to switch to a simplified mode. You can find options in the VLC Preferences to enable Minimal View or customize the interface.
  Save the changes.
• Keyboard Shortcut: you can activate the Minimal View using the keyboard shortcut Ctrl+H
• View Menu The option for activating Minimal View can be activated from the View menu from top right menus

Disclamer

Disclamer: this MR includes the work from @Thrillseekr 2024 GSOC, his work addressed the case of the minimal view implemented in the player. We (rather I) thought that the minimal mode would be simpler if implemented as a root view:

• original idea was that the minimal view is a player view so this was implemented as a player mode (switching to minimal would require pushing the player view)
• having it as a root view, avoids tedious interaction in the player with toolbars, playlist etc...
• minimal view is by nature simple, so it requires only a handful of compoment (player view, background, CSD, key/mouse interaction)

So I updated the branch to implement this. In regard to the work achieved by @Thrillseekr, we decided to submit it as branch containing his original work followed by the modification made to make the minimal mode available globally