Aurora platform abstraction library

[plfiorini]

Create a platform abstraction library called AuroraPlatform.

The compositor needs to access the underlying platform: specifically input and output devices.

We will implement device integration plugins as well as input managers to provide access to to the underlying platform such as drm, wayland, and so on...

AuroraCompositor will use AuroraPlatform to get access to input and output devices.

A new aurora-eglfs plugin will be created in the qtintegration project, using AuroraPlatform and its plugins.

Compositors will always run using the new aurora-eglfs QPA plugin, not the traditional plugins such as wayland-egl or xcb.

Entities:

• Integration: backend for the device integration
• InputManager: backend for the input system
• InputDevice: generic input device
• KeyboardDevice: keyboard
• PointerDevice: pointer
• TouchDevice: touch
• Output: screen
• Session with a factory to create different implementations (such as logind, seatd, noop, ...)

Wayland compositors need to access

• the underlying screens to get hardware information, dpms mode, screen recording, presentation time, etc...
• input devices to get relative pointer motion for pointer lock extension
• hardware layers and direct scanout

A platform abstraction library allows the compositor to access input and output devices, without using Qt private APIs.