frontend: Allow users to download/upload custom parameters

### Current behaviour

When I was talking to @ES-Alexander he commented it would be nice to allow users to download the current parameter configuration before reseting them as a backup

I believe this could be added in the Vehicle setup -> Configure page. I think we can elaborate together if we are going to add a new card for this or insert the button inside an existing card.

### Expected or desired behaviour

When clicking a new download button the current parameters configuration would be downloaded.

### Prerequisites

- [x] I have checked to make sure that a similar request has not already been filed or fixed.

Start in the Vehicle setup → Configure page, which the issue identifies as the intended location. First determine how the current parameter configuration is represented and how reset is handled; done means users can download the current configuration before resetting, with the upload behavior in the title clarified.

Written by the indexing model from the issue text.