- Create a package named after each service in gcloud-java-examples
- Create a package snippet in each service's package to hold README's snippets
- Split Datastore Storage and ResourceManager examples in two
- Create a class for each snippet in the corresponding service package
- Add reference for the READMEs to the corresponding snippet class
- Update package-info.java accordingly

- Remove check for existence in datastore and storage create snippets
- Rename GetOrCreateBlob to CreateBlob, GetOrCreateEntity to CreateEntity
- Use relative links in READMEs
- Remove full snippets in module's READMEs, replaced with link to class