feat: Implement invoice generation and emailing functionality

- Added invoice generation logic using DomPDF.
- Integrated invoice data retrieval from the API.
- Implemented language determination for invoices based on customer data.
- Added options to email invoices to customers and admin.
- Included HTML output option for direct viewing in the browser.
- Ensured proper redirection and error handling throughout the process.

.gitignore

@@ -15,3 +15,11 @@ settings/soveliti/soveliti_settings.php
 assets/database/dev_schema.sql
 assets/database/migration.sql
 assets/database/prod_schema.sql
+migration.sql
+assets/database/migration_triggers.sql
+assets/database/migration_v2.sql
+assets/database/migration_v3.sql
+.DS_Store
+api/.DS_Store
+api/v1/.DS_Store
+api/v2/.DS_Store