Epic listing page should remember list sorting order

Summary

Documentation page: https://docs.gitlab.com/ee/user/project/issues/sorting_issue_lists.html

Our epics are numbered to be displayed correctly in alphabetical order.

Currently the default when going to the Epics list is the starting date order, which isn't meaningful.

It would be best if the sorting order of epics and issues lists in a Group could be ordered always the same, either by remembering the previously set order, or configuring it in settings. This can be achieved by utilizing userPreferencesUpdate mutation similar to how Issues list does.