Deprecation of Qt5 stuff on Arch

Hi, there.

Another Qt5 package (qqc2-desktop-style5) was removed from Arch repos, preventing builds (reported here).

I have tried a quick CI build (no CUDA and no bergamot/rhvoice) without this dependency and with this change:

-DBUILD_QQC2_DESKTOP_STYLE=ON

and it seems to build just fine but then the app would not not launch without qqc2-desktop-style5 installed. I had to install these other packages to be able to launch the app and to make it look like it normally does (I use the default graphic style):

kconfigwidgets5 kiconthemes5 kirigami2

Is this the way to go? Any other suggestions so I can make the changes and submit a MR?

Anyway, I wanted to open an issue first for the heads up related to deprecation of Qt5 packages on Arch (this is the reason ChaoticAUR folks have declined the build btw).

Cheers