win: fix, improve disabling automatic updates #252

- Add script to disable `WaaSMedicSvc` service (#252)
- Refine script granularity for more precise control.
- Introduce detailed documentation for the category and associated
  scripts.
- Fix `ScheduledInstallTime` being set to `3` which schedules updates to
  install at 3 AM.
- Fix `ScheduledInstallDay` is being set to `0` which schedules daily
  update installation.
- Fix `NoAutoUpdate` being set to `0` (enable) instead of `1` (disable).
- Add disabling of missing `wuauserv` service.
- Add parent category for disabling Windows update services for better
  organization.