About page: remove sc-controller

[TraceyC77]

https://getsol.us/solus/about/

The sc-controller software was deprecated. Remove the reference from the page.

[malfisya]

We should review that page more closely. Many of the software mentioned are third party repo software and we are killing it. Gitkraken, Idea, Itch.io.

[Staudey]

itch actually was a main repo package, but was deprecated a long time ago

<!-- No longer feasible to package and ship without enforcing itch-setup and auto-updates //-->
<Package>itch</Package>
<Package>itch-dbginfo</Package>