WorldEdit commands file logging independent of console logging.

**Is your feature request related to a problem? Please describe.**
I can't make WorldEdit log commands to a file without showing them in the server console.
This configuration doesn't work, it won't log commands in the file specified.
`log-commands=false`
`log-file=test.log`

**Describe the solution you'd like.**
Add an option in `worldedit.properties` to only log commands in the file specified and not have them show up in the console.