Enable Helix timegating (#4035)

For commands affected by the timegating, they will continue to use their IRC command equivalent until the 11th of February, 2023.
This is one week before the actual migration is supposed to start. The wording of the date is shaky, so we start a bit before to be sure.
Any highly affected commands will have a temporary setting at the bottom of the General settings page to override the timegating functionality.

Any commands that are affected will also have their changelog entry updated to notify of the timegating. As of this commit, this is only active for /raid

src/controllers/commands/CommandController.cpp

@@ -43,8 +43,10 @@ using namespace chatterino;
 
 bool areIRCCommandsStillAvailable()
 {
-    // TODO: time-gate
-    return true;
+    // 11th of February 2023, 06:00am UTC
+    const QDateTime migrationTime(QDate(2023, 2, 11), QTime(6, 0), Qt::UTC);
+    auto now = QDateTime::currentDateTimeUtc();
+    return now < migrationTime;
 }
 
 QString useIRCCommand(const QStringList &words)