WIP: Refactoring ideas collection

# Refactoring ideas

## Frontend
- [ ] Mmp data types include non mmp related entities, like deletedAt => remove those from mmp types
- [ ] Change flow of application: Async request to create the map, then redirect to the map.
- [ ] Make a guard out of the admin id check in the gateway
- [ ] Make use of a transaction for updateMap call in mapService. Currently, existing nodes are deleted before the json is imported. Thats fine but should be wrapped inside a transaction block. Otherwise the import fails and the map is completly empty.
- [ ] Refactor file download logic, use `window.URL.createObjectURL` and try to to remove fakeLink, e.g. by using `open`
```
public static downloadFile(name: string, content: string) {
const fakeLink = document.createElement('a');

const blob=new Blob([content]);
const objectUrl = window.URL.createObjectURL(blob);

fakeLink.href = objectUrl;
fakeLink.download = name;

document.body.appendChild(fakeLink);

fakeLink.click();

window.URL.revokeObjectURL(objectUrl)
document.body.removeChild(fakeLink);
}
```

Choose one unchecked item rather than treating this collection as a single change. Start by locating the named entry points—mapService.updateMap, the gateway admin ID check, or the file download logic—and confirm the current behavior before changing it. Done means one focused refactor is completed without altering the intended application behavior and its relevant checks pass.

Written by the indexing model from the issue text.