This commit is a refactoring of code that has been located in the main
package. We introduce separate packages for the main application, jobs,
notifications, and request handlers.
Dependencies are injected from the main application, this will make
testing easier.
- remove the old code and its dependencies
- perform some refactoring and fix notifications
- add TODO tags for observed shortcomings
- rename voters.go to users.go
- implement health check for SMTP connection
- rename config block mail_server to mail_config
- rename smtp server settings
- move mail notification settings to mail_config
- improve navigation templates
- prepare routes for user management
