Integrate countdown inside the player instead of static message ouside of the player when autoplay is enabled

**Is your feature request related to a usage problem (not a bug)? Please describe.**
I noticed that there is a static message ("Playing next video in 5 seconds. Click to cancel.") when waiting for the next video to appear. I think its better to let the user know how much time they have left instead of just guessing when the 5sec will be over.

This will enhance user experience in 2 ways:
1. Users will exactly know how much time is left when the new video starts.
2. Users will exactly know how much time is left to prevent the next video from playing.

**Describe the solution you'd like to see implemented**
Integrate the countdown into the player.

This is because there are 3 flaws in the current implementation:
1. When fullscreen is enabled u cant see the message appear.
2. When Fullwindow is enabled u cant see the message appear.
3. When PIP is enabled u cant see the message appear.