ExceptionLayoutRenderer extension

Extended the Exception layout renderer, so the exception data can also be rendered for the log entries.

The _data_ property can be added to the exception format setting (can be used for inner exception as well):

```
${exception:format=type,message,data}
```
And the output will be similar to this:

```
System.Exception Some exception message  testkey: testvalue;testkey2: moredata
```