Ability to control the filename of the generated pdf receipts

### Description

Current implementation will, on the completion of a data process step, create a PDF receipt for that step and automatically assign a filename equal to the name of the app. While this works to some point when you have one layout and one data step, it gets a bit confusing for the users when you have multiple layout and data steps as you will end up with multiple files with the same name.

We should be able to provide some control over the filename or at least differ based the layout it belongs to as a minimum. However being able specify some sort of pattern like: `{appName}-{layoutsetId}-{date}.pdf` with a few useful known variables would go a long way. Or a simple interface that can be implemented and injected when generating the PDF.

Other variables that could come in handy:
* {userName}
* {userId}
* {language}
* {orgNumber}

A good implementation that easily allows for extending these could be an alternative as well.

### Additional Information

_No response_

### Tasks

_No response_

### Acceptance Criterias

- [ ] Being able to differ between pdf's generated on different data steps and with different data models
- [ ] Being able to specify the filename with a few selected variables