factor out kdump_get_arch_recommend_crashkernel
    
    Resolves: bz1895258
    Upstream: Fedora
    Conflict: None
    
    commit 105c01691ac200e7ce71795b2f41b64dd6cf3b58
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Tue Nov 16 11:26:31 2021 +0800
    
        factor out kdump_get_arch_recommend_crashkernel
    
        Factor out kdump_get_arch_recommend_crashkernel to prepare for
        kdump-anaconda-plugin for example to retrieve the default crashkernel
        value.
    
        Note the support of crashkenrel.default is dropped.
    
        Reviewed-by: Pingfan Liu <piliu@redhat.com>
        Reviewed-by: Philipp Rudo <prudo@redhat.com>
        Signed-off-by: Coiby Xu <coxu@redhat.com>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>