Account namespace updates: part 1 (#893)

* Rename accountable types

* Merge conflicts

* Fix broken tests

* Add back sidebar changes

test/models/depository_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class DepositoryTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end