3f91fbf frontend: add manage.py 'shell' command and 'run'

Authored and Committed by praiskup 4 years ago
    frontend: add manage.py 'shell' command and 'run'
    
    But still keep the 'runserver' backward compatibility command, it is
    mentioned in docs and blog posts.
    
    Merges: #1107
    Relates: #1100