Instructions on how to use links(external and embedded) for different SDKs

[rjalander]

No description provided.

[afrittoli]

We have not defined yet how SDKs will implement external and embedded links; this is a discussion that we wanted to have after the v0.4.0 release to avoid delaying the release too much.
For now, once the schemas are fixed, we should limit the implementation to being able to produce and parse embedded links like any other part of the events.

[rjalander]

@afrittoli @xibz
In Java SDK we have a few tests to validate examples(now conformance), and the tests also need to validate the links in conformance json samples.
As we haven't defined on links implementations from SDKs, will comment the assertions to validate the conformance json files for now?