Do not run the integration tests in forks

[lslezak]

Problem

• The integration tests use a schedule and are run automatically every day
• If the integration test fails it reports a failure on our IRC channel
• But if it fails in a fork it is just spamming the IRC and we cannot do anything about it anyway

Solution

• Disable scheduled runs in forks, allow only explicit manual run (if somebody wants to be sure it still works fine)
• Never run the IRC notification in forks, even in manual runs

Additional Fix

• Run the test 5 minutes earlier to have enough time to check the failure and possibly discuss it on the daily call