Drop concatenated title of add dialog for association_table widget
    
    As for now the default title of add dialogs, which are
    initialized from 'association_table' widget, is set to something
    like 'Add ${other_entity} into ${entity} ${primary_key}',
    where 'other_entity' and 'entity' are also translatable texts.
    This construction is used via method 'create_add_dialog' of
    'association_table' widget for the all 'Add' actions within
    details of entities.
    
    Such concatenation leads to a bad quality translation and
    should be changed to an entire sentence.
    
    From now a mentioned title is taken from a spec and should be
    specified explicitly.
    
    Fixes: https://pagure.io/freeipa/issue/7712
    Fixes: https://pagure.io/freeipa/issue/7714
    Reviewed-By: Serhii Tsymbaliuk <stsymbal@redhat.com>