nixos/xserver: abort when encountering unknown xorg drivers (#486149)

- `pocket-id` has been updated to version 2 that contains [breaking changes](https://pocket-id.org/docs/setup/major-releases/migrate-v2).

- `services.xserver` will now throw an error if an X11 driver specified in  `videoDriver(s)` cannot be found. Previously, unknown drivers would be silently ignored.

- `asio` (standalone version of `boost::asio`) has been updated from 1.24.0 to 1.36.0. Some breaking changes were introduced between these

  two versions, and the one affected most was the removal of `asio::io_service` in favor of `asio::io_context` in 1.33.0. `asio_1_32_0` is

  retained for packages that have not completed migration. `asio_1_10` has been removed as no packages depend on it anymore.

    services.xserver.videoDrivers = mkIf (cfg.videoDriver != null) [ cfg.videoDriver ];

    # FIXME: somehow check for unknown driver names.

    # We ignore unknown drivers here because they may be resolved by other modules (e.g., the Nvidia

    # module). We assert that all specified drivers were eventually found in the assertions below.

    services.xserver.drivers = flip concatMap cfg.videoDrivers (

      name:

      lib.optional (videoDrivers ? ${name}) (

        assertion = cfg.upscaleDefaultCursor -> cfg.dpi != null;

        message = "Specify `config.services.xserver.dpi` to upscale the default cursor.";

      }

    ];

    ]

    ++ map (driver: {

      assertion = builtins.elem driver (builtins.catAttrs "name" cfg.drivers);

      message = "Unknown X11 driver ‘${driver}’ specified in `services.xserver.videoDrivers`.";

    }) cfg.videoDrivers;

    environment.etc =

      (optionalAttrs cfg.exportConfiguration {