Support simplified access to save&restore root node

[georgweiss]

The save&restore root node is created with a hard coded unique ID. Clients cannot be expected to know the value of this id, so this PR adds the ability to query for the root node using a GET call to <context>/root or <context>/node/root. To get child nodes of the root client may use a GET call to <context>/node/root/children.

• Testing:

  • The feature has automated tests
  • Tests were run
  • If not, explain how you tested your changes

• Documentation:

  • The feature is documented
  • The documentation is up to date
  • Release notes:
    • Added an entry if the change is breaking or significant
    • Added an entry when adding a new feature

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud