Application prefs section (#2758)

* Add code for creating/managing apps to settings section

* Add specs for app changes

* Fix controller spec

* Fix view file I pasted over by mistake

* Add locale strings. Add 'my apps' to nav

* Add Client ID/Secret to App page. Add some visual separation

* Fix rubocop warnings

* Fix embarrassing typo

I lost an `end` statement while fixing a merge conflict.

* Add code for creating/managing apps to settings section

- Add specs for app changes
- Add locale strings. Add 'my apps' to nav
- Add Client ID/Secret to App page. Add some visual separation
- Fix some bugs/warnings

* Update to match code standards

* Trigger notification

* Add warning about not sharing API secrets

* Tweak spec a bit

* Cleanup fixture creation by using let!

* Remove unused key

* Add foreign key for application<->user

db/migrate/20170427011934_re_add_owner_to_application.rb

@@ -0,0 +1,8 @@
+class ReAddOwnerToApplication < ActiveRecord::Migration[5.0]
+  def change
+    add_column :oauth_applications, :owner_id, :integer, null: true
+    add_column :oauth_applications, :owner_type, :string, null: true
+    add_index :oauth_applications, [:owner_id, :owner_type]
+    add_foreign_key :oauth_applications, :users, column: :owner_id, on_delete: :cascade
+  end
+end