feat: Deduplicate in more places (#6464)

Deduplicate:
- In the REPL
- In `store_from_base64()`, which writes avatars received in headers
- In a few tests
- The saved messages, broadcast, device, archive icons
- The autocrypt setup message

1-2 more PRs, and we can get rid of `BlobObject::create`,
`sanitise_name()`, and some others

deltachat-repl/src/cmdline.rs

@@ -939,7 +939,7 @@ pub async fn cmdline(context: Context, line: &str, chat_id: &mut ChatId) -> Resu
             } else {
                 Viewtype::File
             });
-            msg.set_file(arg1, None);
+            msg.set_file_and_deduplicate(&context, Path::new(arg1), None, None)?;
             msg.set_text(arg2.to_string());
             chat::send_msg(&context, sel_chat.as_ref().unwrap().get_id(), &mut msg).await?;
         }