Feature Request: Multiple Backup Rules

[batonac]

Preface
I understand that an "Advanced Backups" script is available that provides quite a bit more flexibility for configuring backup jobs, but I would argue that this fails to provide a solid path forward for WPCD users for both the lack of UI, and the lack of automatic configurability.

The Advanced Backup tool sorta made sense when the need to support additional backup targets was so apparent, but since that's now resolved with the addition of the S3 Endpoint URL parameter, I firmly believe that the path forward for WPCD users lies in improving the existing UI-integrated backup tool.

Description
The UI-integrated backup tool is lacking flexible configurability. There are lots of things I could wish for, but for now, I propose that the next step forward would be to introduce a child-table with separate backup rules around the following:

• Backup type: Filesystem, Database, Configuration
• Frequency: Hourly, Daily, Weekly, Monthly, Cron rule
• Local Retention: Number of backups to keep locally.
• Remote Retention: Number of backups to keep remotely.

Implementation
Since WPCD Panel is based on Meta Box, a Meta Box Group should be sufficient for recording these rules. If the frequency parameters are saved as Cron rules to the server, the scheduling should be fairly straight-forward.

I'd also hope for the ability to set global defaults for these backup rules that would be automatically deployed to any new server, similar to the functionality of the current backup defaults.