[Feature] - Add possibility to use Multiple Editor Tabs in the Config Server UI

[MariusBrill]

Is your feature request related to a problem? Please describe. Currently the Config Server UI only supports a single Editor frame. Clicking another file results in switching this very frame to the contents of said file. In every modern IDE, clicking on a file opens a new Editor Tab. This makes editing the contents of multiple files much easier.

Describe the solution you'd like The solution should work similar to modern IDEs and UI-based text editors as shown in the screenshot below.