title: How to customise django inline admin form's delete function
body: <p>How do I customise django's inline admin form's delete action. My admin.py setup is below.</p>
  
  <pre><code>#admin.py
  class ChildModelInline(admin.TabularInline):
      model = ChildModel
      can_delete = True
  
  #admin.py
  @admin.register(ParentModel)
  class ParentModelAdmin(admin.ModelAdmin):
      inlines = [ChildModelInline,]
  </code></pre>
  
  <p>The ChildModel is related to the ParentModel by a models.ForeignKey field. I would like to be able to select multiple child object on the ParentModel's Inline Form to be removed, but not delete the child object from the database, just remove the ForeignKey relationship in the child obj.</p>
  
  <p>Thank you!</p>