Remove features/admin/settings.feature

Signed-off-by: Rémy Coutable <remy@rymai.me>

features/admin/settings.feature

-@admin
-Feature: Admin Settings
-  Background:
-    Given I sign in as an admin
-    And I visit admin settings page
-
-  Scenario: Help text
-    When I set the help text
-    Then I should see the help text
-    And I go to help page
-    Then I should see the help text
-    And I logout
-    Then I should see the help text