ksqlDB auto close windows

Good afternoon. The problem is very simple, when you use **window functions (TUMBLING**) with **emit final**, then the window is closed only when the next message arrives, and it can come in 5 hours and the client will get the message after 5 hours instead of the 10 seconds delay.
The current implementation needs to be improved. Include in ksqldb internal mechanisms to close windows automatically


```
SELECT userId, count(*),
from_unixtime(WINDOWSTART) as Window_Start,
from_unixtime(WINDOWEND) as Window_End,
from_unixtime(max(ROWTIME)) as Window_Emit
FROM s_t1
WINDOW TUMBLING (SIZE 10 SECONDS)
GROUP BY userId
EMIT FINAL;
```

We have a large company and wanted to use your technology, but this problem changes everything.
@mjsax @big-andy-coates @JimGalasyn @vcrfxia

Start with the reported TUMBLING window query using EMIT FINAL and trace the ksqlDB windowing implementation; the payload does not name a source file or test. Done means a 10-second window closes and emits its final result without waiting for another message, including when the next message arrives hours later.

Written by the indexing model from the issue text.