monorepo: Finalize repository tree layout

Reorganize files from `vfio` and `vfio-user`, and layout them like a
monorepo. `Cargo.toml`s of workspace and `vfio-user` are modified
accordingly.

Signed-off-by: Ruoqing He <[email protected]>

Author: RuoqingHe

Cargo.toml

@@ -1,3 +1,3 @@
 [workspace]
-members = ["vfio-bindings", "vfio-ioctls"]
+members = ["vfio-bindings", "vfio-ioctls", "vfio-user"]
 resolver = "2"

vfio-user/Cargo.toml

@@ -18,7 +18,7 @@ serde = { version = "1.0.151", features = ["rc"] }
 serde_derive = "1.0.149"
 serde_json = "1.0.93"
 thiserror = "2.0.12"
-vfio-bindings = { version = "0.4.0", features = ["fam-wrappers"] }
+vfio-bindings = { version = "0.4.0", path = "../vfio-bindings", features = ["fam-wrappers"] }
 vm-memory = { version = "0.16.0", features = ["backend-mmap", "backend-atomic"] }
 vmm-sys-util = "0.13.0"