Not sure why we had these here, but alignment on a packed struct seems somewhat
nonsensical (after all, it's fields are packed as closely together as possible
so what would alignment refer to?) removing seems fine and fixes compilation with
latest Zig:
```
/Users/slimsag/Desktop/hexops/mach/gpu-dawn/libs/mach-glfw/src/hat.zig:8:20: error: unable to override alignment of packed struct fields
up: bool align(@alignOf(u8)) = false,
^
/Users/slimsag/Desktop/hexops/mach/gpu-dawn/libs/mach-glfw/src/mod.zig:10:23: error: unable to override alignment of packed struct fields
shift: bool align(@alignOf(c_int)) = false,
``` ^
Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
* move key values in an enum
* bitmask for key modifiers
* export Key type and move key fns
instead of exporting the key file, export Key enum.
functions related to the Key type are moved into the enum as well so that they get exported with the type
