Remove v1 collectibles endpoint

[hectorgomezv]

/v1/chains/<chain_id>/safes/<safe_address>/collectibles shouldn't be available anymore, since the provider (Transaction Service) has deprecated the related endpoint.

Solution
Two options here:

• Remove the endpoint completely (including Swagger specification).
• Keep the endpoint but send a deprecation note to the clients indicating the new endpoint to use (v2).

[fmrsabino]

The V1 collectibles endpoint was removed in the migration to https://github.com/safe-global/safe-client-gateway-nest