cli: Support --seed on rad clone

Allows specifying one or more seeds to clone from. This is useful for
cloning private repositories which are not in the routing table.

radicle-cli/tests/commands.rs

@@ -1683,6 +1683,47 @@ fn rad_init_private_clone() {
         .unwrap();
 }
 
+#[test]
+fn rad_init_private_clone_seed() {
+    let mut environment = Environment::new();
+    let alice = environment.node(Config::test(Alias::new("alice")));
+    let bob = environment.node(Config::test(Alias::new("bob")));
+    let working = environment.tmp().join("working");
+
+    fixtures::repository(working.join("alice"));
+
+    let alice = alice.spawn();
+    let mut bob = bob.spawn();
+
+    test(
+        "examples/rad-init-private.md",
+        working.join("alice"),
+        Some(&alice.home),
+        [],
+    )
+    .unwrap();
+
+    bob.connect(&alice).converge([&alice]);
+
+    formula(
+        &environment.tmp(),
+        "examples/rad-init-private-clone-seed.md",
+    )
+    .unwrap()
+    .home(
+        "alice",
+        working.join("alice"),
+        [("RAD_HOME", alice.home.path().display())],
+    )
+    .home(
+        "bob",
+        bob.home.path(),
+        [("RAD_HOME", bob.home.path().display())],
+    )
+    .run()
+    .unwrap();
+}
+
 #[test]
 fn rad_publish() {
     let mut environment = Environment::new();