[webOS] Screensaver support

[sundermann]

Description

Provides proper screensaver support. Needs update of webos-userland on the mirrors. I have adjusted the BASE_URL temporarily.

Motivation and context

Videos were playing fine before without being interrupted by the screensaver. However, it was only visually disabled. From when the screensaver would normally have kicked in, we would still need an additional button press on the remote to interact with kodi again. This PR adds proper screensaver support using the luna bus.

How has this been tested?

LG OLED77C28LB (webOS 7/22)

What is the effect on users?

Fixes needing to press a button twice after some time

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• My code follows the Code Guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the Contributing document
• I have added tests to cover my change
• All new and existing tests passed

[sundermann]

Squashed the fixups