Cleanup seeder.ts

[speigg]

• Cleaned up seeder logic to use feathers api directly, rather than underlying sequelize model (which will be removed after we update to Feathers 5 schemas)
• Improved template matching logic, to eliminate the need for checking the Model schema for unique columns
• Brought back logic to filter out *setting tables, which only need to be seeded once
• Refactored new Promise(async () => {}) anti-pattern
• Added npm run prepare-database to .vscode/launch.json config for easier debugging