Update translations.txt after Fares v2 addition into GTFS

### Describe the problem

[translations.txt](https://gtfs.org/schedule/reference/#translationstxt) is a GTFS file that allows producers that operate in regions that have multiple official languages to provide translations to user-facing names.
Several features of the [GTFS Fares v2 extension project](https://gtfs.org/extensions/fares-v2/) have been adopted in GTFS recently, and some of them apply to the scope of translations.txt.

### Use cases

Allowing to match the fare product name and potentially the fare media name to the names used by the agency rider-facing information, in places where several official languages exist.

### Proposed solution

Extend the [translations.txt](https://gtfs.org/schedule/reference/#translationstxt) file with:

- `fare_product_name`: The name of the fare product as displayed to riders.
- `fare_media_name`: Name of the fare media (e. g. Clipper card).

We need a producer and a consumer to be able to adopt this in GTFS. If you are either and you're interested in supporting this, please comment on this issue or write us at specification@mobilitydata.org.

### Additional information

First GH issue opened with the new template 🏄, this is great!