Running uberjar for the server

This PR creates a template `-main` for running the application. The only mode supported at the moment is an integration mode. This will allow us to launch the sandbox for engineering to start tinkering with.

I also changed the name of `create-local-image-storage` to `create-image-storage` to better reflect the abstraction.

I also fixed a minor discrepancy with the `option-map` in `vignette.util.thumbnail` that enables the modes to be sent to the thumbnail script properly.

The build/run process is as follows:

```sh
lein uberjar
java -jar vignette/target/vignette-standalone.jar -I -p 8081
```

/cc @nmonterroso 
Now that there's integration with WikiaLogger, I wonder if this would be better as a simple message "generating thumbnail failed" with the other values as part of the context object.