Modernize the RDMO frontend

[jochenklar]

Rationale / Begründung

RDMO uses AngularJS 1.6 and Bootstrap 3 for the front-end. Both libraries are not up to date anymore.

Affected

Just changing the technology should not change the user experience significantly. Instance would need to adapt to the new technology, though.

Minimal functionality

Not using AngularJS 1.6 and Bootstrap 3 anymore. We already discussed some replacement technology stack:

• React, Webpack, Bootstrap5
• Alpine.js and Bootstrap5

[jochenklar]

We decided to use a combination of React and Redux.