Provide media/files at UUIDs additionally to node IDs

[aksm]

What

Related to esmero/strawberryfield#220 and esmero/strawberryfield#230.

When downloading media/files for ADOs they are currently accessed at unstable node IDs. As we do for the ADOs themselves, they should be provided at stable UUIDs.

The suggested path will be as follows:
/do/{uuid}/file/{uuid}/download/{format}

@DiegoPino Not sure if I'm describing this correctly so please correct me if I'm wrong or need to clarify.

[DiegoPino]

@aksm please add the suggested path/pattern discussed last night with the team. Thanks. Also this goes into format_strawberryfield since the controller for the current one is there (check the route.yml files). Thanks!

[DiegoPino]

Solved via 005b14a