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 
To be honest, I wasn't too concerned with optimal :). I just wanted to make sure the images were in the expected path in integration mode. In "service" or "production" mode this copy won't happen. There are only a few images so I'm not too worried about it.