Store id of the export vm to task table for future reference

Signed-off-by: walteryang <walteryang47@users.noreply.github.com>
Add getAllFinishedTasksForVm db function for backup delete usage

Signed-off-by: walteryang <walteryang47@users.noreply.github.com>
Update delete task logic

task cannot be deleted by vmId, but deleted by vmId and
backupName(backup vm/snapshot id)

Signed-off-by: walteryang <walteryang47@users.noreply.github.com>
Move getIsoDomainToExport to TimerSDKTask

The method will be needed elsewhere

Signed-off-by: walteryang <walteryang47@users.noreply.github.com>
Add delete backup logic

Signed-off-by: walteryang <walteryang47@users.noreply.github.com>