Implement customer management domain with authorization and API enhancements

- Introduced a new customer management domain, including entities, services, handlers, and forms for customer operations.
- Added JWT-based user authorization settings in the configuration file for both user and customer management.
- Updated API endpoints to reflect the new structure, including changes to health check and user management routes.
- Enhanced Swagger documentation to include new customer-related endpoints and authorization details.
- Refactored the Makefile to include a target for generating API documentation.
- Removed obsolete documentation files to streamline the project structure.

Makefile

@@ -1,6 +1,6 @@
 # Tender Management Backend Makefile
 
-.PHONY: help build run test clean docker-build docker-run
+.PHONY: help build run test clean docker-build docker-run docs run-docs
 
 # Default target
 help:
@@ -92,6 +92,7 @@ lint:
 	@golangci-lint run
 
 # Generate API documentation
+# Marked as .PHONY to avoid collision with the top-level docs directory
 docs:
 	@echo "Generating API documentation..."
 	@swag init -g cmd/web/main.go -o cmd/web/docs