[Feature] Interface of Table Creation and Relational API

The interfaces of table currently support `list_table` and `drop_table`, while the creation of table API is required for users to launch a project.

Considering CnosDB support both internal and external table import, we'd better design different interfaces for them.

Start by reviewing the existing list_table and drop_table interfaces in the Python client. Clarify the intended relational API for table creation and how internal and external table imports should differ. Done means the interface design and supported creation behavior are agreed and implemented.

Written by the indexing model from the issue text.