feat: Add option to specify attached databases in the DataCloudConnection

[ankoh]

This commits adds an option to specify AttachedDatabases in the DataCloudConnection.

Example:

Properties properties = new Properties();
properties.setProperty("databases.0.path", "lakehouse:<tenant-id>");
properties.setProperty("databases.0.alias", "lakehouse");

We enforce that indexes are provided sequentially, without holes and sort the attached databases by index.

Note that this PR will have merge conflicts with Adrians property revamp.
I'll rebase once this lands early next week.

[salesforce-cla]

Thanks for the contribution! It looks like @ankoh is an internal user so signing the CLA is not required. However, we need to confirm this.