[Wiki] Fix and update release notes
[Wiki] Fix and update release notes

* Move release notes for 1.15.2 to the correct section.
* Also include release notes for 1.14.4 for the sake of completeness.

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr