------------------
* BREAKING: Connections are now stored in a namespace instead of being submodules.
New usage:
.. code-block:: python
from sql_connectors import connections
client = connections.example_connection()
Instead of:
.. code-block:: python
from sql_connectors import example_connection
client = example_connection()
* New ``Storage`` abstract class can be extended to implement different backend
* Configuration is now handled by ``Traitlets``. Default storage class can be specified
with ``SQL_CONNECTORS_STORAGE`` env var and the connection string or path can be
specified with ``SQL_CONNECTORS_PATH_OR_URI``