Adapt onto prototype to output underlying xml models for multiple bpmn diagrams

[WolfgangDaniel]

• [x] Create a backend api call that retrieves all xml models for all models specified by id
• [x] Create a frontend that enables to select multiple of the available models and a submit button that triggers an api call that generates an RPM UI log based on the selected models (for now all this call does is call the new other api call that retrieves all the different xml models and prints them in the backend for proof)

[WolfgangDaniel]

Still need to properly connect the frontend api call with the backend api call, currently axios error