Add DataSpannerTest annotation

[eddumelendez]

Currently this configuration is required in order to test a Spanner repository. This PR help to improve that configuration in some way. But previously required some commands to be executed

gcloud config configurations create emulator

gcloud config set auth/disable_credentials true

gcloud config set project test-project

gcloud config set api_endpoint_overrides/spanner http://localhost:9020/

gcloud spanner instances create test-instance --config=emulator-config --description="Test Instance" --nodes=1

gcloud spanner databases create test-database --instance test-instance --ddl "CREATE TABLE TestTable (key INT64, value STRING(MAX)) PRIMARY KEY (key)"

In order to improve from the test perspective, I think #2357 will help a lot and may this proposal will do the same. Also would like to think about how these initiatives will integrate with testcontainers, for example, I have a PR https://github.com/testcontainers/testcontainers-java/pull/2690/files which will use docker sdk but it requires additional installation in order to use alpine images so there is an issue requesting images for the other emulators, something similar to spanner.

The same can be done for datasotre, firestore and I already have something in progress but looks pretty similar. Also, considering pubsub but thinking more about it.

See gh-2281

[eddumelendez]

/cc @saturnism

[dmitry-s]

@eddumelendez thanks for your contribution! We have redesigned our test-support module and this PR will be very useful when we start working on it.