This change updates the structure of the OpenDC frontend in order to
improve the maintainability of the frontend.

This change simplifies the logic and components of the projects page and
reduces its dependency on Redux for simple operations.

This change updates the project structure to become flattened.
Previously, the simulator, frontend and API each lived into their own
directory.

With this change, all modules of the project live in the top-level
directory of the repository. This should improve discoverability of
modules of the project.