[Enhancement]: add support for Spanner Emulator

[fabbrik]

Problem

I need support for Spanner Emulator so I can run integration tests using Google Technology Stack

Solution

Created a project and a test that pulls the spanner-emulator image from gcp registry.

Benefit

additional support to GCP technology stack

Alternatives

my current alternative is to use batch scripts to create, run and remove the container in the CI pipeline.

Would you like to help contributing this enhancement?

Yes

[fabbrik]

I do the code changes ready for PR submission.

[HofmeisterAn]

Please also see the previous attempt: #865.