replace dynamic require calls to be customizable

[paul-marechal]

Related: eclipse-theia/theia-ide#74 (comment)

Currently we use dynamic require calls in various backend places. This causes issues when trying to Webpack the backend.

To fix that issue, I think the best approach would be to expose a common script re-exposing require. This way we can replace imports of to that module with a custom one using Webpack in order to replace the actual method used.