feat: add API to expose one shots

CHANGELOG:

### Added
- [#1079](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/1079) Add API to expose one shots

Related card: https://trello.com/c/wH0P6sbR/1726-preparar-api-per-exposar-els-os

---

• One Shot Catalog API:

➜ curl -X GET \
➜   -H  "accept: application/json" \
➜   -H  "api-key: $APIKEY" \
➜   -H  "Accept-Language: $ODOOLANG" \
➜   "$URL/api/one-shot-catalog/?product_code=SE_SC_REC_MOBILE_2_SHARED_UNL_51200" | jq
{
  "pricelists": [
    {
      "code": "21IVA",
      "one_shots": [
        {
          "code": "CH_SC_OSO_SHARED_10GB_ADDICIONAL",
          "name": "10 GB Addicionals Compartides",
          "price": 1,
          "minutes": 0,
          "data": 10240
        },
        {
          "code": "CH_SC_OSO_SHARED_20GB_ADDICIONAL",
          "name": "20 GB Addicionals Compartides",
          "price": 1,
          "minutes": 0,
          "data": 20480
        }
      ]
    }
  ]
}