Updates README to use YAML instead of XML

[alparslanavci]

Fixes #96.

[hasancelik]

I think we should keep XML config as a separate section. Most of our users still use XML configuration. WDYT? @alparslanavci @leszko

[alparslanavci]

@hasancelik yes, we can keep them both, but I think it might be a good push to pass YAML config.

[hasancelik]

Afaik, IMDG core will continue to support XML for a long time so promoting YAML for Kubernetes service discovery is good idea but for AWS, I am not sure.

[nfrankel]

IMHO, XML is far superior to YAML, especially when the configuration is a bit large. That some want to use YAML is fine (...).

I'd suggest the documentation offers both, just as Spring does with Java and Kotlin support. Please see how it looks here: https://docs.spring.io/spring-framework/docs/5.2.x/spring-framework-reference/core.html#beans-factory-instantiation. There's one tab for Java, one for Kotlin so it doesn't impair readability.

[leszko]

LGTM 👍

If you find a way to create tabs in GH Readme (like suggested by @nfrankel), then it's a good idea to have YAML/XML/Java as tabs. If not, then yeah, let's keep anyway all options in the config XML, YAML, and JAVA. We are moving to YAML everywhere, but @hasancelik is right that a lot of AWS users probably still use XML.

[alparslanavci]

Ok, I added back the XML configuration samples.