Add back MoreRed support

I removed this in aa0d544bba, way back in
late 2021. Looks like it's been updating in the meantime and I hadn't
noticed, so add it back.

I've simplified the code a little bit, to make use of our new capability
helpers, but otherwise it's almost exactly the same :D.

buildSrc/src/main/kotlin/cc-tweaked.java-convention.gradle.kts

@@ -59,6 +59,7 @@ repositories {
             includeGroup("cc.tweaked")
             includeModule("org.squiddev", "Cobalt")
             // Things we mirror
+            includeGroup("commoble.morered")
             includeGroup("dev.architectury")
             includeGroup("dev.emi")
             includeGroup("maven.modrinth")