* move Descriptor to sdkapi, add test
* rename Descriptor to sdkapi
* precommit
* Move the rest of the sdkapi
* use alias for Observation and Measurement
* Changelog
* pr num
* comment Measurement and Observation
* swap comments
* move->moved
* Update README
Move project status to top of project documentation and add explicit
warnings that this project may introduce breaking changes.
* Add disclaimer to public packages docs
* Use explicit warning in README