Add API for getting supported OS flavors per Scylla version

[vladzcloudius]

We'd like to get an API that would return supported Operating Systems (e.g. "Ubuntu 24.04", "RHEL 8.0", etc.) per Scylla version.
The API should return a result in JSON.

The information in question is similar to what we have on

• https://enterprise.docs.scylladb.com/stable/getting-started/os-support.html
• https://opensource.docs.scylladb.com/stable/getting-started/os-support.html

[annastuchlik]

@dgarcia360 I'm adding it to our backlog.