docs-krita-org updated with 4.2 material.

[Wolthera]

Hi everyone,

We're hoping to have Krita 4.2 released by the end of the month(that
is, the end of may). The manual has been updated with all the new
features we've added. I've also fixed some translation issues with the
manual, in particular translated images now actually work. This
however required a reorganisation of the images folder.

Because we have been moving over to gitlab for the main Krita
repository, we've also moved the manual there. The merge request
workflow works a little smoother for that, but I think scripty hasn't
been configured to talk to invent.kde.org yet. There's also a flurry
of typo fixes coming in from several people.

For the 4.1 manual that you have been translating, for the languages
that were on the official site we took all the epubs (in different
languages) and will be archiving them on KDE servers, so your
translation work for those was not in vain.

So in short:
1. We moved to gitlab, but scripty isn't pulling the info from it yet,
so the po files aren't updating right now. I'll need some help from
you guys with this.
2. We've merged the draft branch, as well as resolved a whole bunch of
issues with translation of images, so once the po files are pulled
there's a whole bunch of updating that'll need to happen.
3. We've got backups of the translated manuals as epubs, we're in the
process of uploading these.

I am super inexperienced with maintaining a project like this, so I
hope this isn't all too confusing, still, thank you to everyone who
has gone out of their way to do typo fixes while translating :)

Hopefully everything will go well,
-- 
Wolthera

(CC-ing the kimageshop mailinglist with this)