Create database backup method

[Moltensnor]

Creates a verticle that makes backups of the database.
Added new property values:

• BACKUP_FREQUENCY: The frequency of when to make the backups. This can be daily, hourly, weekly, monthly.
• BACKUP_TIME: The preferred time to backup the database. It will make the backup on this time if the frequency is not set to hourly. Otherwise it will do it every hour from this time.
• SAVED_BACKUPS: The maximum allowed backups inside the backups folder.

The verticle has a scheduler which uses these values to schedule the backup. It is also connected to the eventbus so a backup can also be created from a request.

Closes #35. Depends on #24.