feat(init): add init crate with declarative boot manifest, boot sequence, supervisor and shutdown stubs

Also: make types from_raw/raw const fn, add create_process/kill/delegate/revoke to userspace syscall stubs.

crates/userspace/src/syscall.rs

@@ -31,6 +31,22 @@ pub fn request_pages(count: usize) -> usize {
     arch::syscall1(SYS_REQUEST_PAGES, count)
 }
 
+pub fn create_process(create_cap: usize) -> usize {
+    arch::syscall1(SYS_CREATE_PROCESS, create_cap)
+}
+
+pub fn kill(process_cap: usize) -> usize {
+    arch::syscall1(SYS_KILL, process_cap)
+}
+
+pub fn delegate(slot: usize, to: usize, permissions: usize) -> usize {
+    arch::syscall2(SYS_DELEGATE, slot, to)
+}
+
+pub fn revoke(slot: usize) -> usize {
+    arch::syscall1(SYS_REVOKE, slot)
+}
+
 pub fn send(endpoint: usize, w0: usize, w1: usize, w2: usize, w3: usize) -> usize {
     arch::syscall5(SYS_SEND, endpoint, w0, w1, w2, w3)
 }