Player slider movement animation and text transitions

[nvllz]

1dbb8c98-7783-4870-9bd5-8a37765a603c.mp4

It looks much more natural than on the recording,

[z-huang]

I like the text animation, but not the slider movement. I want to know precise location when I drag the seek bar and don't want to wait for the dot to animate.

[z-huang]

If possible, transition for artwork will be great.

[nvllz]

@z-huang this wasn't the case as I managed the drag gesture to not wait for the slider (no animation), but tapping "next song" caused the animation to glitch, which made me drop the slider movement feature. But I kept the timer transition and added a fade to the miniplayer, as shown below.

2bf69c16-434a-46f7-97f9-1396f56baa8a.mp4

As for the cover animation, I may try to implement it later in another PR, as it will require more work.

[z-huang]

I noticed a detail: the vertical position of texts may change if the two texts are of different size (e.g. English and Chinese). Can you fix it?

[nvllz]

Can't do much about it, as it seems to be a compose bug.

[nvllz]

Tomorrow I'll publish a more advanced PR with fixed animations for these labels containing certain characters.