Many fixtures have similar code for writing the pid & ports files or
for handling HTTP requests. This commit adds an AbstractHttpFixture
class in the test framework that can be extended for specific testing purposes.
This does away with the deprecated `com.google.api-client:google-api-client:1.23`
and replaces it with `com.google.cloud:google-cloud-storage:1.28.0`.
It also changes security permissions for the repository-gcs plugin.
Similarly to what has been done in for the repository-s3 plugin,
this commit moves the fixture test into a dedicated
repository-gcs/qa/google-cloud-storage project.
It also exposes some environment variables which allows to
execute the integration tests against the real Google Cloud
Storage service. When the environment variables are not
defined, the integration tests are executed using the fixture
added in #28788. Related to #29349.
Mark Vieira
Alpar Torok
Tanguy Leroux
Albert Zaharovits