This PR changes the add data form behavior to create connector files instead of model files. There are also some form modifications to simplify the process of adding a new connector, e.g., removing sql and name when providing a connection string in postgres.

• type: connector
• use ConfigProperties, nuke SourceProperties
• clean up yupSchemas

Closes https://linear.app/rilldata/issue/APP-242/create-connector-files-not-model-files

The follow-up of this ticket is form modifications.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!