Add a new hook: 92-crashkernel.install
    
    To track and manage kernel's crashkernel usage by kernel version,
    each kernel package will include a crashkernel.default containing the
    default `crashkernel=` value of that kernel. So we can use a hook to
    update the kernel cmdline of new installed kernel accordingly.
    
    Put it after all other grub boot loader setup hooks, so it can simply
    call grubby to modify the kernel cmdline.
    
    Signed-off-by: Kairui Song <kasong@redhat.com>
    Acked-by: Baoquan He <bhe@redhat.com>