ChmK our solution to stop needing KHTML to support CHM?

[Albert Astals Cid]

I've started a simple CHM viewer based on QWebEngine.

https://tsdgeos.blogspot.com/2020/05/chmk-simple-chm-viewer.html

If we get it to a usable state (it's almost there, needs a bit more UI, but shouldn't be that hard to do) I think we can drop CHM support in Okular thus getting rid of KHTML that will most probably never make it to Qt6.

Merge Requests welcome :)

Cheers,
  Albert