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/init/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "init"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+types = { workspace = true }
+userspace = { workspace = true }