ABI summary

• mirplatform ABI bumped to 23
• mirserver ABI bumped to 57

Enhancements

• [Wayland] Error on invalid xdg_surface size
• [MirAL] add a socket_fd_of(Application) function (for use with authenticating in snaps with apparmor)
• [MirAL] Add WaylandExtensions::conditionally_enable(). (Fixes #2194)
• Add display-scale option
• Try harder to pick a working GBM framebuffer (Some drivers don't support rendering to RGBX GBM buffers)

Bugs fixed

• [Wayland] Extension names in configuration and global names should match. (Fixes #2208)
• fix Miral shell text on Arch
• Differentiate between active surfaces and surfaces with keyboard input. (Fixes #1626, #2189)