wasmtime: add CLI options for pre-opened TCP listen sockets (#3729)

This patch  implements CLI options to insert pre-opened sockets.

`--listenfd` : Inherit environment variables and file descriptors following
               the systemd listen fd specification (UNIX only).

`--tcplisten <SOCKET ADDRESS>`: Grant access to the given TCP listen socket.

Signed-off-by: Harald Hoyer <harald@profian.com>

Cargo.lock

@@ -1585,6 +1585,17 @@ version = "0.0.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95f5690fef754d905294c56f7ac815836f2513af966aa47f2e07ac79be07827f"
 
+[[package]]
+name = "listenfd"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e514e2cb8a9624701346ea3e694c1766d76778e343e537d873c1c366e79a7"
+dependencies = [
+ "libc",
+ "uuid",
+ "winapi",
+]
+
 [[package]]
 name = "lock_api"
 version = "0.4.4"
@@ -3472,6 +3483,7 @@ dependencies = [
  "humantime 2.1.0",
  "lazy_static",
  "libc",
+ "listenfd",
  "memchr",
  "more-asserts",
  "num_cpus",