Cosmos Java repo has moved

We're moving to the azure-sdk-for-java repo! 🎉🎉🎉

## V3 🧀🚚

The contents of v3 have been moved to azure-sdk-for-java.

V3 issues and feature requests will move to azure-sdk-for-java. Any new issues opened on this repo that are V3 bugs or feature requests will be moved to the azure-sdk-for-java repo.

Once we've switched development to the new repo, we'll update the readme to make this clear.

## V2 🧊

For the time being V2 code and issues will stay in this repo. If you're not sure if it's a V2/V3 issue, you can use the azure-sdk-for-java and we'll manage it there.

Once V2 is end of life'd (not announced yet; 1 year's notice will be given), this repo will be archived.