API "projects" call: include information about the default project

The resulrs of the API "projects" call should contain an indicator, which project is the default

added Rest API label

@piotr.gawron this is a non-critical issue, feel free to close.

created branch 1423-api-projects-call-include-information-about-the-default-project to address this issue

mentioned in merge request !1629 (merged)

changed milestone to %v17.0.0~beta.0

mentioned in commit c15bd52f

closed with merge request !1629 (merged)

Tested, OK.