SR: Support schema references

[Haarolean]

[alexandrelimait]

I use the registry schema with schemas in json and there are references to other schemas in my schemas, when I try to access a topic I get the http 404 message and the error in the console, in the network part everything is normal, I am adding here as requested in discord

[ccontino84]

Any updates on this? @Haarolean could you at least describe in an abstract way what needs to be done in the code so that people who are interested could look into it? Thanks!