Make service definitions more succinct

## Make service definitions more succinct

### Tasks
- Where a service is defined as `$app->share(function () use ($app) {...`, replace with `$app->share(function ($app) {` since Pimple attempts to inject the app.

### Additional Notes
- It probably only introduces a minuscule amount of overhead, but it's cleaner to read, it's how Silex is built to work, and it provides a better example for projects to follow.