GDB-11621 Run cronjob as root, to make sure that backup rotation works correctly.

[vanxa]

Description

Run cronjob as root user to make sure that the backup rotation works correctly (without exposing aws cli to low-priv users)

Related Issues

GDB-11621

Changes

• Run cronjob as root
• Make sure backup log file is initialized correctly during provision

Checklist

• I have tested these changes thoroughly.
• My code follows the project's coding style.
• I have added appropriate comments to my code, especially in complex areas.
• All new and existing tests passed locally.

[viktor-ribchev]

Changes look legit, but need to be tested.

[vanxa]

Tests confirm that the backup and rotation is working as expected.
Setup backup with retention count 30, backup running every minute:

Waiting for the 30 items to be uploaded

After a few minutes, some items have been rotated

Log has correct access flags

[vanxa]

As discussed with @viktor-ribchev ,
changed the user to gdb_backup - if backup is enabled. This user will be the only one with access to aws cli.
If backup is disabled, simply restrict aws cli to root only.

[viktor-ribchev]

This comment needs updating