[KPhotoAlbum] New website design

[Tobias Leupold]

Hi all!

> - https://www.kphotoalbum.org/download.html -> Gettin involved link seems
> to be broken/ish (points to a dir structure, subfolder shows the actual
> content).
Thanks for the hint, I (hopefully) fixed this. Now I hope that the homepage
will be updated automagically through my git push ;-)

> Also, someone (or I :) should try to build KPA from scratch at some point
> and confirm if these instructions are still up-to-date:
> https://community.kde.org/KPhotoAlbum/build_instructions
Those seem to be for a Debian based system. Here on Gentoo it's nothing more
than e. g. "mkdir build && cd build && cmake -G Ninja .. && ninja -j5" or
such.

Another thing that I noticed: I personally think that the www-subdomain is
completely pointless. I redirect all www-subdomains on all of my hompages to
the subdomain-less variant. For KPA, we actually do the opposite. What about
having https://kphotoalbum.org/?

Cheers, Tobias