feat(bench) adding random schedule for benchmark tasks

[sameer-in]

Adding random hour and minute in benchmark default schedult

[wideawakening]

made some minor changes for checks to pass

• benchmark task was conflicting in backend. cleaned it up and checks are ready to merge
• updated docs/lint

@sameer with checks on green feel free to merge. some minor things though

• regarding schedule changes, could you update the bench docs accordingly? guess the change is to add some entropy, so we could tell the user to check the final scheduled time on secure / check the tf plan / state
  https://github.com/sysdiglabs/terraform-aws-secure-for-cloud/blob/update-bench-task-schedule/modules/services/cloud-bench/README.md?plain=1#L6
• does it make sense to make same move in gcp and azure modules too?

[sameer-in]

Yup. I will add the changes in the doc. I am also doing these changes for gcp and azure.