[Feature request] Digital clock overlay

[lodesmets]

I made a new overlay to create a digital clock with WLED. (7 segment style)

I already made a pull request, can someone take a look at it? #1916

I'm currently 3D printing the last parts. Once this is done I will write more documentation on how it works.

[Aircoookie]

Hi!
That is awesome, I need to review and merge your PR (and also #1873, which is very similar), soon :)