FixYTPlayer

Fix the YouTube player to the top of the window.
Click the pin button in the left top of the player to toggle between fixed and unfixed.

# Release Notes
- v1.0.5: Fix: #cinematics layering issue by changing fixed element from #player to #player-container-outer
- v1.0.4: Fix the z-index relationship between header, side menu and player.
- v1.0.3: Enable pin button on end-of-playback screen.
- v1.0.2: Fix bug that does not recognize the player Extensions could not run due to YouTube.
- v1.0.1: Minor fixes and refactoring.
- v1.0.0: published.