Create build-kernel.yml for Darkmatter kernel

[guranotfound]

This workflow automates the building of the Darkmatter kernel with various configurations and patches.

[hmtheboy154]

1. Xanmod patches are already here
2. If you made this just to inject KSUNext (or SukiSU ?) with SUSFS then please create another workflow for this.
3. It would be better if you can make workflow for newer branch. Or else rename the yml to make it reflect that it only build 1 kernel