Add ability to download schema references

[ferozed]

Added ability to download schema references.

A new configuration downloadReferences: Boolean was added to DownloadSchema.

When set to true, and the schema has references, the referenced schemas are also downloaded. This will allow POJO generation to succeed from schema with references.

[ImFlog]

@ferozed the integration tests are failing. There is a special gradle task for them that you should be able to run locally (if you have Docker installed).

Also, after looking a bit in the confluent code I wonder if there are not an integrated way to do this directly when parsing the schema using `toNormalize before retrieving the schema ?

[ferozed]

Also, after looking a bit in the confluent code I wonder if there are not an integrated way to do this directly when parsing the schema using `toNormalize before retrieving the schema ?

Right... but this will only work for AVRO schemas?

[ferozed]

Yeah... so the integration tests are failing because the new config I added is a required value. Is there any way to make it optional? I tried using @Optional annotation but that didnt work.

[ferozed]

Ok... i kinda worked around it by putting the downloadReferences configuration per subject, instead of it being global.

[ImFlog]

Starts to look good !
Only issue is that you have no way to set the flag to true as no property in the extension is mapped to the subject.
You should probably add an integration test with the flag set to true and verify that 2 files are created.

Also we should update the readme with the new parameter.

[ImFlog]

LGTM !
I think I will try to release this with #160.

I keep you posted when I found the time to do so.

Thank you for the contribution 🙏