Delete messages more thoroughly (and at all) (#2114)

- Make sure delete_expired_messages and housekeeping runs once a day
- delete more info about messages when putting them to trash (esp. also
delete txt_raw, from_id and to_id as we don't need those anymore, so
they are data that was unnecessarily kept)

fix #1926, fix #2090

Also:

* Nicer test_utils: add send_text() and print_chat()

* Adapt ephemeral messages for testing (make them accurate to the second)

* Add test for ephemeral messages

* Make pop_sent_msg() really pop the last sent message

src/config.rs

@@ -136,6 +136,9 @@ pub enum Config {
 
     /// address to webrtc instance to use for videochats
     WebrtcInstance,
+
+    /// Timestamp of the last time housekeeping was run
+    LastHousekeeping,
 }
 
 impl Context {
@@ -175,6 +178,13 @@ impl Context {
             .unwrap_or_default()
     }
 
+    pub async fn get_config_i64(&self, key: Config) -> i64 {
+        self.get_config(key)
+            .await
+            .and_then(|s| s.parse().ok())
+            .unwrap_or_default()
+    }
+
     pub async fn get_config_bool(&self, key: Config) -> bool {
         self.get_config_int(key).await != 0
     }