AO3-6672 Allow some admins to set a generic username #4849

Job	Run time
rake db:otwseed	1m 11s
rspec spec/controllers	12m 36s
rspec spec/models	7m 4s
rspec --exclude-pattern 'spec/{controllers,models}/*/.rb'	8m 38s
cucumber features/admins	6m 45s
cucumber features/bookmarks	5m 51s
cucumber features/collections	7m 6s
cucumber features/comments_and_kudos	7m 1s
cucumber features/gift_exchanges	8m 0s
cucumber features/importing	2m 54s
cucumber features/other_a	10m 45s
cucumber features/other_b	6m 8s
cucumber features/prompt_memes_a	4m 6s
cucumber features/prompt_memes_b	3m 32s
cucumber features/prompt_memes_c	4m 55s
cucumber features/search	6m 32s
cucumber features/tag_sets	3m 15s
cucumber features/tags_and_wrangling	7m 2s
cucumber features/users	5m 16s
cucumber features/works	12m 38s
	2h 11m 15s

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