Add CLI for sdgx

[wunder957]

Problem

We currently only provide Python code for interaction, it is more difficult for other languages to call sdgx code directly.

Proposed Solution

One possible approach is to add a CLI that enables the user to specify input and output paths for cleaned data, models.

Examples

$sdgx fit --model=CTGAN --table_path=/path/to/table.csv --output_path=/path/to/model  --param_path=/path/to/config.toml
$sdgx sample --model_path=/path/to/model --num_rows=1000 # Generate 1000 samples with model

Additional context

Since each model has a different sample and fit method, I thought it would be easier to add a --param_path and make it point to a file for configuration.

Perhaps we could introduce a plugin system so that we can not only easily add new models, but also support user plugins to add their own algorithms without modifying this project, and pulggy is a good choice.