Add registry validators (#350)

Fixes #96

## Motivation and Context

See #96

## How Has This Been Tested?

Has some unit and integration tests, still needs proper testing of the
different registry types

## Breaking Changes

Yes, new package uploads will need extra verification

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

cmd/registry/main.go

@@ -47,7 +47,6 @@ func main() {
 	switch cfg.DatabaseType {
 	case config.DatabaseTypeMemory:
 		db = database.NewMemoryDB()
-		registryService = service.NewRegistryServiceWithDB(db)
 	case config.DatabaseTypePostgreSQL:
 		// Use PostgreSQL for real registry service
 		// Create a context with timeout for PostgreSQL connection
@@ -61,10 +60,6 @@ func main() {
 			return
 		}
 
-		// Create registry service with PostgreSQL
-		registryService = service.NewRegistryServiceWithDB(db)
-		log.Printf("PostgreSQL database URL: %s", cfg.DatabaseURL)
-
 		// Store the PostgreSQL instance for later cleanup
 		defer func() {
 			if err := db.Close(); err != nil {
@@ -78,6 +73,8 @@ func main() {
 		return
 	}
 
+	registryService = service.NewRegistryService(db, cfg)
+
 	// Import seed data if seed source is provided
 	if cfg.SeedFrom != "" {
 		log.Printf("Importing data from %s...", cfg.SeedFrom)