Refactoring in ScheduledReports to remove useless indentation

I have refactored the code a bit to make it (hopefully) more readable.

The diff is going crazy, but basically I have just replaced this:

```php
if (self::manageEvent($reportType)) {
    // big block of code
}
```

By this:

```php
if (! self::manageEvent($reportType)) {
    return;
}

// big block of code
```

It's not much but it removes one level of indentation in almost the whole class (almost all the methods were like that), which is kind of nice.

(by the way this is one of the "object calisthenics" rules)