Kernel: Implement supplementary groups

This code has very ugly file parsing code. I have to create API
for reading files line by line in kernel space...

This allows users to open framebuffer/input files without root.

Mounting has to be moved to userspace soon. It makes no sense to
hard code permissions for every (device) file.

kernel/kernel/Device/FramebufferDevice.cpp

@@ -22,7 +22,7 @@ namespace Kernel
 		if (g_boot_info.framebuffer.bpp != 24 && g_boot_info.framebuffer.bpp != 32)
 			return BAN::Error::from_errno(ENOTSUP);
 		auto* device_ptr = new FramebufferDevice(
-			0666, 0, 0,
+			0660, 0, 900,
 			DevFileSystem::get().get_next_dev(),
 			g_boot_info.framebuffer.address,
 			g_boot_info.framebuffer.width,