Provide APIs to check whether direct binary access is enabled for certain deployment

As per the documentation of direct binary access feature [0], the only way to determine whether the feature is enabled for a certain deployment with a blobstore is to upload a binary to a blobstore and see whether it gets succeeded or not.

In some cases, this is not feasible like when you need to make a low level decision to enable certain functionality based on the presence of the feature. You do not have the access to any binary at that moment.

It would be a helpful improvement to provide APIs which can be involved to determine whether cloud storage provides the DBA feature or not.

[0] https://jackrabbit.apache.org/oak/docs/features/direct-binary-access.html