Declare the first python base image

[alafanechere]

We want to port over the prototyping work achieved in #29477 to master.

Definition of done

• Connector base images can be declared in a dedicated python package under airbyte-ci/connectors/base_images
• A versioning logic allows us to easily incrementally declare a new base image version while keeping the previous version declaration
• The base image can be imported in our pipelines package to be used in the python connector build process
• A first base image version is declared