Kernel minimization (#334)

* adds patch to remove unused kernel components

* new boards, rebase patches to match

* rename boards for deployment

boards/nordic/nrf52840_dongle_opensk/build.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("cargo:rerun-if-changed=layout.ld");
+    println!("cargo:rerun-if-changed=../../kernel_layout.ld");
+}