New digikam website source available from KDE's git server

[Simon Frei]

The website indeed looks amazing - thanks once again to everyone that
makes it possible!

The following is already in nitpick mode, but I wanted to have it
written down such that I don't forget (a new component in the bug
tracker would probably be helpful, e.g. "Website"):
 - The Meta subchapters should not be hidden behind the main "Meta"
topic in the bottom menu bar.
 - In my opinion the meta chapters would fit better under Documentation.
 - About subtopics should be alphabetically ordered (now it is maybe
ordered by importance, but I think that's confusing).
 - In the download page the two-line "Linux AppImage" resulting in
non-aligned 64-/32-bit links looks not so nice. I think it would look
better if it was somehow squeezed into one line or all three titles
(Windows, Mac, ...) aligned centrally and using the same amount of
vertical space.