Enforce deprecation message format with EOL for google provider package

[moiseenkov]

This PR introduces unification for deprecation messages formatting within Google's provider package by following:

1. Updated the pre-commit hook check-code-deprecations so it enforces a specific message structure containing the end of life date for the deprecated entity. According to the deprecation policy discussed here, this deadline doesn't enforce removal of the deprecated entity from the source code, it only increases transparency and predictability for users, so they knew how much time do they have for the changes on their side.
2. Another reason for this change is preparation for the cleaning-up process as Google's provider package has collected a lot of old legacy code and we'd be happy to finally clean it up.
3. These changes work only within an airflow/providers/google scope.
4. The default EOL is at least six months ahead.
5. Some classes and methods have assigned earlier deadlines because they have been deprecated for a very long time already and can be removed earlier or their API is shut down and they are not working already.