Summary:
Original commit: 72d69d515c76fee486eb2661333f4a063c0881f0 / D46632
If a customer tries to take a yba backup with prometheus data and releases, it can
take some time to complete. If they have HA setup, the HA background process will also trigger a backup, overwriting
some of the files from the yba-ctl backup. To get around this,
yb_platform_backup.sh now stages into a temp directory that is
timestamped

Test Plan:
ran backup and validated new target directory is used
and backups are correct

Reviewers: anijhawan, nbhatia, nsingh, muthu

Reviewed By: nsingh

Subscribers: nikhil

Differential Revision: https://phorge.dev.yugabyte.com/D47090