[FEATURE] Multiple Steam Input configurations in "Tray mode"

[Alia5]

Describe the solution you'd like

When SISR is launched on its own (not from Steam), it currently uses a single Steam Input configuration: that of the "SISR Marker Shortcut".

To provide more flexibility SISR should allow users to switch the used Steam Input config at runtime,
using to be added GUI elements in the SISR overlay

The GUI should list:

• Every non-Steam game the user has added to Steam
• Every Steam game the user has (if possible to query)
• Provide a way to select arbitrary steam Input Configurations via Steam protocol URL (steam://controllerconfig/appId/configId)
• Provide a way to select and arbitrary Steam Game (AppId) for games purchased or retrieved to other Storefronts or means ;)