Plasma-integration and branches

[David Edmundson]

We've discussed a few times an issue with plasma-integration and
supporting Qt5 and Qt6 clients.

When we release Plasma 6, we need to ensure that a Qt5 and Qt6 builds
are released. We need users to have both as they are plugins where
users might have Qt5 and Qt6 codebases.

Right now master branch supports both. The Qt branches are massively
divergent for Qt 5 and 6 clients and we're filling it with a huge mess
of if statements and it's a pain to work on. There's patches blocked
on needing ifdefs.

The proposal is we make a Plasma/6.0-qt5 branch based off the current
Plasma/5.27 branch but fixing the version numbers.

At release time we will release a tarball from Plasma/6.0 and
Plasma/6.0-qt5 with different tarball names.
Translations would have to be considered. Pragmatically translations
will be identical to 5.27, though it's not guaranteed.

Before we go ahead, are there any objections and can release team
people and i18n confirm they're ok with the above.

David