Backup Management: Add an ability to specify the number of retries for Scheduled backups before operation fails

User story:
As a PMM user, I need to be able to specify the retry info related to the scheduled backup job,  when I'm scheduling a backup so that PMM automatically retries accordingly whenever something goes wrong with the job execution.

UI/UX:
see the design attached to https://jira.percona.com/browse/PMM-8155

Acceptance criteria

• This is about Automatic retries
• the User can specify the max number of retries to be executed
• the User can specify the time interval between retries 

Out of scope:

• Manually triggered retries

How to test:
TBD

Details:
TBD