This PR adds support for authorized views:

Authorized views are logical views of tables that give you fine-grained access control of your Bigtable data. An authorized view is a subset of a table that you configure to include specific table data. Then you grant access to the authorized view separately from access to the table.

To implement this feature, we added a new _ApiSurface super class for the Table object, and moved all logic into the super class. Then, we added a new subclass for AuthorizedView, alongside the existing Table. Authorized views should be functionally identical to tables from the client-library level, but they can be configured to only read/write to sepecific regions of the database