Walkthrough Example: Migrate a dbt project to sqlmesh without reprocessing data using the table migration guide

[sungchun12]

This should be narrative in style and use "I" language similar to this existing walkthrough: https://sqlmesh.readthedocs.io/en/stable/examples/incremental_time_full_walkthrough/#model-configuration

We want the community to feel equipped with scenario-based docs as that's how most people think when they want to get hands-on with SQLMesh.