[Feature] Support CLI arguments as alternative to config file

[GTonehour]

Currently, all configuration is stored in the JSON configuration file:

pg-diff -f /path/to/config.json

Most CLI tools (like migra, sqldef...) allow configuration options to be passed directly as CLI arguments. This is convenient for one-off comparisons and scripting with dynamic configuration.

Example usage:

pg-diff --sourceClientDatabase db1 --targetClientDatabase db2