Import ocean protos with buf

[altafan]

At the moment this project imports vulpemventures/ocean as a git submodule to import the protos and stubs.
Instead, we should configure buf to import those protos as dependencies in a buf.yaml, then generate the python stubs if necessary (they've been committed so maybe this step is not needed).

You can take this repo as reference for the work to be done.. we should replicate the same scaffolding.

[tiero]

Ping on this, to remove submodules