refactor: complete seed column definitions and move location

[lawrenceadams]

Sumamry

This pull request includes significant updates to the seeds configuration in the dbt_project.yml file and the addition of detailed seed configurations in the seeds/synthea/_sources.yml file. The main changes involve enabling the synthea schema and adding comprehensive column type definitions for various tables.

Updates to dbt_project.yml:

• Removed table schema definitions.

Additions to seeds/synthea/_sources.yml:

• Added detailed seed configurations with column type definitions for synthea output.

Why Bother?

• Removes ambiguity
• If using other seed files/larger seed files columns may not be sniffed in their entirety and this will result in errors downstream when an incorrect type (e.g. ZIP looks like a numeric type by default - causing issues when doing string parsing)

[lawrenceadams]

Thank you @katy-sadowski !! Some silly mistake from myself...