Updated `Program.cs` to conditionally select the database connection string based on an environment variable or configuration setting. Introduced a new variable `cnnStrName` for determining the use of a migration test database.
Added a new setting `"UseDbMigration": true` in `appsettings.json` to enable the migration test database, and included the corresponding connection string as `"DbMigrationTest"`. Removed the previous `"Dev"` connection string.
- Updated namespace for `ResetEmailTemplateCommand` and added a constructor for flexible initialization.
- Introduced `ChangedWhen` property in `UpdateEmailTemplateCommand` to track modification time.
- Refactored `UpdateEmailTemplateCommandHandler` for improved email template retrieval logic.
- Modified `EmailTemplateController` method signatures and logic for clarity and consistency.
- Added `EmailTemplate` entry in `appsettings.json` for database trigger configuration.
- Updated DependencyInjection to include new command handler.
- Modified CreateEnvelopeReceiverCommand for nullable responses.
- Altered SQL command in EnvelopeReceiverAddReadSQL.
- Refactored EnvelopeReceiverController with new dependencies and improved CreateAsync method.
- Expanded appsettings.json with additional configuration settings.
- Introduced new DTOs for signatures and receivers in CreateEnvelopeReceiverDtos.
