Revert pull request #22042

Revert "Fix code quality test failures"

This reverts commit 8c55e11d1f.

Revert "Fix celery send_activation_email task failure"

This reverts commit 810eea0e51.

Revert "Convert Account Activation Emails to edx-ACE"

This reverts commit 7984c37a4f.

common/test/test_sites/test_site/templates/emails/activation_email.txt

@@ -0,0 +1,16 @@
+<%! from django.utils.translation import ugettext as _ %>
+
+${_("Thank you for signing up for Open edX! To activate "
+"your account, please copy and paste this address into your web "
+"browser's address bar:")}
+
+% if is_secure:
+  https://${ site }/activate/${ key }
+% else:
+  http://${ site }/activate/${ key }
+% endif
+
+${_("If you didn't request this, you don't need to do anything; you won't "
+    "receive any more email from us. Please do not reply to this e-mail; "
+    "if you require assistance, check the help section of the "
+    "Open edX web site.")}

common/test/test_sites/test_site/templates/emails/activation_email_subject.txt

@@ -0,0 +1,3 @@
+<%! from django.utils.translation import ugettext as _ %>
+
+${_("Your account for Open edX")}