Issue 49987: Add lineage endpoint to Rlabkey

https://www.labkey.org/home/Developer/issues/issues-details.view?issueId=49987

Tasks:
- [x] Rlabkey - experiment-lineage.api to get parent/child relationships - 3h
- [x] Add RlabkeyTest case - 1h
- [x] code review - 1h
- [x] submit package to CRAN
- [x] TC review and merge - 0.5h