Add Bookmark endpoints specifications and update TSP version to 0.3.0

The specifications of newly introduced endpoints for managing bookmarks
of experiments are added to the API.yaml and API-proposed.yaml.
Also, TSP version is udpated to 0.3.0 from 0.2.0.

Signed-off-by: Kaveh Shahedi <[email protected]>

Author: kavehshahedi