Simplify Dependency management

[dmohns]

Reason: The project uses Rush for the backend part. The frontend part was moved into another repository, but the code was kept in the backend repo (see above).

This makes usage of Rush obsolete (Rush was designed to manage mono-repos of many interdependent projects) and complicates the setup a lot.

Rush seems to be configured to use PNPM. There are some build instructions using yarn and npm is used as well.

Also, the Node version isn’t pinned to the minor version. The Dockerfiles just say node:20-alpine So, upgrades might happen unintentionally.

Steps:

• Consolidate all build steps, local build etc.. to use a single Node package manager.
• Remove Rush and all rush related configuration files.

Definition of done: The frontend and backend application are managed using a single package manager. As a developer, the only prerequisite is to have the correct dependency manager installed.

[dmohns]

This has a dependency on the build pipeline. We can only start working on it, once we have full control over how the project is built and deployed.