AO3-6565 Move admin user search to Elasticsearch, add past emails and username search #4954

Job	Run time
rake db:otwseed	1m 15s
rspec spec/controllers	13m 22s
rspec spec/models	5m 42s
rspec --exclude-pattern 'spec/{controllers,models}/*/.rb'	8m 9s
cucumber features/admins	8m 20s
cucumber features/bookmarks	4m 42s
cucumber features/collections	6m 37s
cucumber features/comments_and_kudos	7m 23s
cucumber features/gift_exchanges	6m 58s
cucumber features/importing	2m 41s
cucumber features/other_a	11m 37s
cucumber features/other_b	6m 48s
cucumber features/prompt_memes_a	4m 25s
cucumber features/prompt_memes_b	3m 36s
cucumber features/prompt_memes_c	5m 23s
cucumber features/search	7m 41s
cucumber features/tag_sets	3m 20s
cucumber features/tags_and_wrangling	6m 46s
cucumber features/users	5m 22s
cucumber features/works	13m 3s
	2h 13m 10s

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