Drop usage of deprecated __secure__ and secure arguments and https-url config
This fixes the following warnings: DeprecationWarning: [3.25] __secure__ argument is deprecated DeprecationWarning: [3.25] secure argument is deprecated Accordingly, we now require cubicweb >= 3.25. Notice that we drop a test case which sole purpose was to check that things work with https-url option. Since this option does not exist anymore, the test is now meaningless. On the other hand, we extend the remaing tests for notification view (test_reset_password) to now check for the presence of instance URL in sent email.