[Docs] Improve Per Event Projection Processing Timeout

[rmfaheem]

The following is feedback received from a customer in ticket: 111276

A suggestion for a piece of documentation improvement. It was not clear to me that "Per Event Projection Processing Timeout" was a new setting on the projection itself. It uses the same name in the docs as the Event Store Server setting "ProjectionExecutionTimeout" so I thought they were one and the same.

It is also not clear from the documentation how these two settings interact with each other. From my brief looking into it it seems that the servers "ProjectionExecutionTimeout" acts as a default for the "Per Event Projection Processing Timeout" setting on each projection created. Any projection created BEFORE you change the "ProjectionExecutionTimeout", will keep whatever it had before.

For example if I start event store server with "ProjectionExecutionTimeout" of 250ms, then create a projection it has a "Per Event Projection Processing Timeout" of 250ms. I then stop the server, change the "ProjectionExecutionTimeout" to 1000ms. Then start the server again and view the projection I created before, it still has a "Per Event Projection Processing Timeout" of 250ms.

Whereas in V5 "ProjectionExecutionTimeout" was just the value used by every projection.