Remove unused SQL queries and update email template handling

- Deleted multiple unused SQL query files from the cms-service.
- Refactored email template handling in the cms-service to improve clarity and maintainability.
- Updated environment variable loading in both cms-service and lms-service to use dotenvy for better configuration management.
- Added a new .env.dev file for local development with database and SMTP configurations.
- Set default value for `certificates_enabled` in the shared common models.

.env.dev

@@ -0,0 +1,40 @@
+# Database URLs for local development
+CMS_DATABASE_URL=postgresql://user:password@localhost:5432/openccb_cms
+LMS_DATABASE_URL=postgresql://user:password@localhost:5432/openccb_lms
+
+# General fallback
+DATABASE_URL=postgresql://user:password@localhost:5432/openccb_cms
+
+# JWT Secret
+JWT_SECRET=dev_jwt_secret_change_in_production
+
+# Logging
+RUST_LOG=debug
+
+# AI Configuration
+# Providers: 'openai' or 'local'
+AI_PROVIDER=local
+OPENAI_API_KEY=
+
+# Local AI (Ollama & Whisper) - Production (HTTPS with SSH tunnel)
+PROD_WHISPER_URL=http://host.docker.internal:8080
+
+# SMTP for local development
+SMTP_ENABLED=true
+SMTP_HOST=mailpit
+SMTP_PORT=1025
+SMTP_FROM=OpenCCB Dev <dev@norteamericano.com>
+SMTP_USERNAME=
+SMTP_PASSWORD=
+
+# Next.js public variables for local development
+NEXT_PUBLIC_CMS_API_URL=http://localhost:3001
+NEXT_PUBLIC_LMS_API_URL=http://localhost:3002/lms-api
+NEXT_PUBLIC_STUDIO_DOMAIN=localhost
+NEXT_PUBLIC_LEARNING_DOMAIN=localhost
+
+# MySQL for courses integration (local)
+MYSQL_DATABASE_URL=mysql://user:password@host.docker.internal:3306/courses_db
+
+# SAM Diagnostico DB (local)
+SAM_DIAGNOSTICO_DATABASE_URL=postgresql://user:password@host.docker.internal:5434/sam_db