radicle: Did improvements

Add conversion from Did to PublicKey through a From implementation.

Add FromStr implementation.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett

radicle/src/identity/did.rs

@@ -46,12 +46,26 @@ impl From<crypto::PublicKey> for Did {
     }
 }
 
+impl From<Did> for crypto::PublicKey {
+    fn from(Did(key): Did) -> Self {
+        key
+    }
+}
+
 impl From<Did> for String {
     fn from(other: Did) -> Self {
         other.encode()
     }
 }
 
+impl FromStr for Did {
+    type Err = DidError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Self::decode(s)
+    }
+}
+
 impl TryFrom<String> for Did {
     type Error = DidError;