win: fix persistent update disabling /w tasks #272

This patch improves the existing functionality for disabling Windows
Updates. It ensures that the disabling of automatic updates is more
persistent, addressing previous shortcomings.

This commit introduces the "Disable Windows Update scheduled tasks"
category, enabling users to persistently turn off automatic background
updates.

Supporting changes include:

- Improve `DisableScheduledTask`:
  - Add the ability to elevate privileges.
  - Add the ability to disable tasks upon script reversion to match the
    correct default operating system state.
  - Fix warning output not being correctly formatted upon script
    reversion.
- Add the ability to disable tasks upon script reversion in
  `DisableScheduledTask` to match the correct default operating system
  state.
- Add a comment to clarify the rationale behind not disabling certain
  Windows services.
- Ensure consistent casing (all uppercase) for Windows environment
  variables in documentation.
- Ensure consistent and right casing of Windows folder names in scripts
  and their documentation.