Cleaning some bundle bugs which confused Jenkins(cherry picked from commit 2119cbdc0d52eef5acc87d3ed3f9906368cc10c2)
Adding fastercsv gem(cherry picked from commit 42bd7d32596561451ad02402937770a45d4f8157)
Use csv_pirate instead of fastercsv(cherry picked from commit fc0985c1a45b9e9cbc1bded2e6fe4bdb997cfcf7)
Enable /activities.csv and /activities/all_activities.csv

For [#44414205]. This gem is handy but uses method names which lead to opaque code.(cherry picked from commit a66e5078e54becd4f72a9d6b2cc59240ac38dddc)
Enables user export through /admin/users.csv

This is the rest of [#44414205], with a user table including total activity count and public activity count.(cherry picked from commit 4f0d865b33f2286feafb066c70b3a5fa9deabafa)
Link to the CSV for [#44414205]
(cherry picked from commit 88f0e0dd45e9acc1b305abc3c40d20b75a5bf8ac)
rm unnecessary gem versions(cherry picked from commit 69c8ebe6eaaa6ce7eae6c6f13733be11f994e84e)