Only keep the ViGEmBus connection alive while gamepads are attached

[cgutman]

Description

This is a potential workaround for the BSODs reported in #1370. It seems that keeping a ViGEmBus handle alive across a power transition can cause ViGEmBus to crash, so we will just open it when we need it and close it when all gamepads are gone.

As a nice bonus, this allows Sunshine to pick up a new ViGEmBus installation without needing to restart Sunshine. It might also resolve the issue with the ViGEmBus installer rebooting the system (at least when it's just us holding a ViGEmBus handle).

Screenshot

Issues Fixed or Closed

Fixes #1370

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

Branch Updates

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Allow edits from maintainers.

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