feat: Pass encryption key in URL fragment

- Remove encryptionKey from URL
- Use POST method to pass both password and encryption key
- Parse URL fragment to extract the encryption key from the web (using
  javascript) and from the CLI

Fixes #36.

Signed-off-by: Julien Riou <julien@riou.xyz>

src/cmd/copier/main.go

@@ -96,6 +96,11 @@ func handleMain() int {
 	}
 	u.Path = "api/note" + u.Path
 
+	if u.Fragment != "" {
+		*encryptionKey = u.Fragment
+		u.Fragment = ""
+	}
+
 	rawURL = u.String()
 
 	logger.Debug("creating http request")