Similarly to what has been done for s3 and azure, this commit removes
the repository settings `application_name` and `connect/read_timeout`
in favor of client settings. It introduce a GoogleCloudStorageClientSettings
class (similar to S3ClientSettings) and a bunch of unit tests for that,
it aligns the documentation to be more coherent with the S3 one, it
documents the connect/read timeouts that were not documented at all and
also adds a new client setting that allows to define a custom endpoint.
Follow up for #23405.
We remove azure deprecated settings in 7.0:
* The legacy azure settings which where starting with `cloud.azure.storage.` prefix have been removed.
This includes `account`, `key`, `default` and `timeout`.
You need to use settings which are starting with `azure.client.` prefix instead.
* Global timeout setting `cloud.azure.storage.timeout` has been removed.
You must set it per azure client instead. Like `azure.client.default.timeout: 10s` for example.