Add support for unified runtime configuration file

[woksin]

Summary

Adds support for a unified json configuration file called runtime.json but stil supports the old legacy configuration files under the .dolittle folder. Legacy configurations under the .dolittle folder will overwrite configurations provided in the runtime.json configuration file

Added

• Configuration provider for a runtime.json file
• A default runtime.json file for default config similar to what we had before under the .dolittle folder

Deprecated

• Configuration files under the .dolittle folder

[woksin]

This should at somepoint be documented on dolittle.io

[woksin]

As far as I know this should not break any current deployments